<documentation>How to encode positional data quality information. Builds on units.xsd to encode the data needed to describe the positional accuracy of coordinate operations.
Copyright (c) 2002-2005 OGC, All Rights Reserved. For conditions, see OGC Software Notice http://www.opengeospatial.org/about/?page=ipr
This schema encodes the Data Quality (DQ) package of the extended UML Model for OGC Abstract Specification Topic 2: Spatial Referencing by Coordinates. That UML model is adapted from ISO 19111 - Spatial referencing by coordinates, as described in Annex C of Topic 2.
Caution: The CRS package in GML 3.1 and GML 3.1.1 is preliminary, and is expected to undergo some modifications that are not backward compatible during the development of GML 3.2 (ISO 19136). The GML 3.2 package will implement the model described in the revised version of ISO 19111. </documentation>
<documentation>Closeness of the relative positions of two or more positions to their respective relative positions accepted as or being true. </documentation>
<documentation>Ordered sequence of units of measure, corresponding to the row and column index numbers of the covariance matrix, starting with row and column 1 and ending with row/column N. Each unit of measure is for the ordinate reflected in the relevant row and column of the covariance matrix. </documentation>
<documentation>Unordered set of elements in this covariance matrix. Because the covariance matrix is symmetrical, only the elements in the upper or lower diagonal part (including the main diagonal) of the matrix need to be specified. Any zero valued covariance elements can be omitted. </documentation>
<documentation>How to encode datum definitions. Builds on referenceSystems.xsd to encode the data needed to define datums, including the specific subtypes of datums.
Copyright (c) 2002-2005 OGC, All Rights Reserved. For conditions, see OGC Software Notice http://www.opengeospatial.org/about/?page=ipr
This schema encodes the Datum (CD_) package of the extended UML Model for OGC Abstract Specification Topic 2: Spatial Referencing by Coordinates. That UML model is adapted from ISO 19111 - Spatial referencing by coordinates, as described in Annex C of Topic 2.
Caution: The CRS package in GML 3.1 and GML 3.1.1 is preliminary, and is expected to undergo some modifications that are not backward compatible during the development of GML 3.2 (ISO 19136). The GML 3.2 package will implement the model described in the revised version of ISO 19111. </documentation>
<documentation>A datum specifies the relationship of a coordinate system to the earth, thus creating a coordinate reference system. A datum uses a parameter or set of parameters that determine the location of the origin of the coordinate reference system. Each datum subtype can be associated with only specific types of coordinate systems. This abstract complexType shall not be used, extended, or restricted, in an Application Schema, to define a concrete subtype with a meaning equivalent to a concrete subtype specified in this document. </documentation>
<documentation>Set of alternative identifications of this datum. The first datumID, if any, is normally the primary identification code, and any others are aliases. </documentation>
</annotation>
</element>
<elementref="gml:remarks"minOccurs="0">
<annotation>
<documentation>Comments on this reference system, including source information. </documentation>
<documentation>Description, possibly including coordinates, of the point or points used to anchor the datum to the Earth. Also known as the "origin", especially for engineering and image datums. The codeSpace attribute can be used to reference a source of more detailed on this point or surface, or on a set of such descriptions.
- For a geodetic datum, this point is also known as the fundamental point, which is traditionally the point where the relationship between geoid and ellipsoid is defined. In some cases, the "fundamental point" may consist of a number of points. In those cases, the parameters defining the geoid/ellipsoid relationship have been averaged for these points, and the averages adopted as the datum definition.
- For an engineering datum, the anchor point may be a physical point, or it may be a point with defined coordinates in another CRS. When appropriate, the coordinates of this anchor point can be referenced in another document, such as referencing a GML feature that references or includes a point position.
- For an image datum, the anchor point is usually either the centre of the image or the corner of the image.
- For a temporal datum, this attribute is not defined. Instead of the anchor point, a temporal datum carries a separate time origin of type DateTime. </documentation>
<documentation>The time after which this datum definition is valid. This time may be precise (e.g. 1997.0 for IRTF97) or merely a year (e.g. 1983 for NAD83). In the latter case, the epoch usually refers to the year in which a major recalculation of the geodetic control network, underlying the datum, was executed or initiated. An old datum can remain valid after a new datum is defined. Alternatively, a datum may be superseded by a later datum, in which case the realization epoch for the new datum defines the upper limit for the validity of the superseded datum. </documentation>
<documentation>An engineering datum defines the origin of an engineering coordinate reference system, and is used in a region around that origin. This origin can be fixed with respect to the earth (such as a defined point at a construction site), or be a defined point on a moving vehicle (such as on a ship or satellite). </documentation>
<documentation>An image datum defines the origin of an image coordinate reference system, and is used in a local context only. For more information, see OGC Abstract Specification Topic 2. </documentation>
<documentation>Reference to a source of information specifying the values and meanings of all the allowed string values for this PixelInCellType. </documentation>
<documentation>A textual description and/or a set of parameters identifying a particular reference level surface used as a zero-height surface, including its position with respect to the Earth for any of the height types recognized by this standard. There are several types of Vertical Datums, and each may place constraints on the Coordinate Axis with which it is combined to create a Vertical CRS. </documentation>
<documentation>Reference to a source of information specifying the values and meanings of all the allowed string values for this VerticalDatumTypeType. </documentation>
<documentation>Partially defines the origin of a temporal coordinate reference system. This type restricts the AbstractDatumType to remove the "anchorPoint" and "realizationEpoch" elements. </documentation>
<documentation>Defines the origin of a temporal coordinate reference system. This type extends the TemporalDatumRestrictionType to add the "origin" element with the dateTime type. </documentation>
<documentation>A geodetic datum defines the precise location and orientation in 3-dimensional space of a defined ellipsoid (or sphere) that approximates the shape of the earth, or of a Cartesian coordinate system centered in this ellipsoid (or sphere). </documentation>
<documentation>The name by which this prime meridian is identified. The meridianName most common value is Greenwich, and that value shall be used when the greenwichLongitude value is zero. </documentation>
<documentation>Set of alternative identifications of this prime meridian. The first meridianID, if any, is normally the primary identification code, and any others are aliases. </documentation>
</annotation>
</element>
<elementref="gml:remarks"minOccurs="0">
<annotation>
<documentation>Comments on or information about this prime meridian, including source information. </documentation>
<documentation>Longitude of the prime meridian measured from the Greenwich meridian, positive eastward. The greenwichLongitude most common value is zero, and that value shall be used when the meridianName value is Greenwich. </documentation>
<documentation>An ellipsoid is a geometric figure that can be used to describe the approximate shape of the earth. In mathematical terms, it is a surface formed by the rotation of an ellipse about its minor axis.</documentation>
<documentation>Set of alternative identifications of this ellipsoid. The first ellipsoidID, if any, is normally the primary identification code, and any others are aliases. </documentation>
</annotation>
</element>
<elementref="gml:remarks"minOccurs="0">
<annotation>
<documentation>Comments on or information about this ellipsoid, including source information. </documentation>
<documentation>Length of the semi-major axis of the ellipsoid, with its units. Uses the MeasureType with the restriction that the unit of measure referenced by uom must be suitable for a length, such as metres or feet. </documentation>
<documentation>Definition of the second parameter that defines the shape of an ellipsoid. An ellipsoid requires two defining parameters: semi-major axis and inverse flattening or semi-major axis and semi-minor axis. When the reference body is a sphere rather than an ellipsoid, only a single defining parameter is required, namely the radius of the sphere; in that case, the semi-major axis "degenerates" into the radius of the sphere.</documentation>
<documentation>Inverse flattening value of the ellipsoid. Value is a scale factor (or ratio) that has no physical unit. Uses the MeasureType with the restriction that the unit of measure referenced by uom must be suitable for a scale factor, such as percent, permil, or parts-per-million. </documentation>
<documentation>Length of the semi-minor axis of the ellipsoid. Uses the MeasureType with the restriction that the unit of measure referenced by uom must be suitable for a length, such as metres or feet. </documentation>
<documentation>The ellipsoid is degenerate and is actually a sphere. The sphere is completely defined by the semi-major axis, which is the radius of the sphere. </documentation>
<documentation>Top-level property. Used in application schemas to "attach" the styling information to GML data. The link between the data and the style should be established through this property only.</documentation>
<documentation>[complexType of] Top-level property. Used in application schemas to "attach" the styling information to GML data. The link between the data and the style should be established through this property only.</documentation>
<documentation>The value of the top-level property. It is an abstract element. Used as the head element of the substitution group for extensibility purposes.</documentation>
<documentation>[complexType of] The value of the top-level property. It is an abstract element. Used as the head element of the substitution group for extensibility purposes.</documentation>
<documentation>[complexType of] The style descriptor for a graph consisting of a number of features. Describes graph-specific style attributes.</documentation>
<documentation>A definition, which can be included in or referenced by a dictionary. In this extended type, the inherited "description" optional element can hold the definition whenever only text is needed. The inherited "name" elements can provide one or more brief terms for which this is the definition. The inherited "metaDataProperty" elements can be used to reference or include more information about this definition.
The gml:id attribute is required - it must be possible to reference this definition using this handle. </documentation>
<documentation>A non-abstract bag that is specialized for use as a dictionary which contains a set of definitions. These definitions are referenced from other places, in the same and different XML documents. In this restricted type, the inherited optional "description" element can be used for a description of this dictionary. The inherited optional "name" element can be used for the name(s) of this dictionary. The inherited "metaDataProperty" elements can be used to reference or contain more information about this dictionary. The inherited required gml:id attribute allows the dictionary to be referenced using this handle. </documentation>
</annotation>
<complexContent>
<extensionbase="gml:DefinitionType">
<sequenceminOccurs="0"maxOccurs="unbounded">
<choice>
<elementref="gml:dictionaryEntry">
<annotation>
<documentation>An entry in this dictionary. The content of an entry can itself be a lower level dictionary or definition collection. This element follows the standard GML property model, so the value may be provided directly or by reference. Note that if the value is provided by reference, this definition does not carry a handle (gml:id) in this context, so does not allow external references to this specific entry in this context. When used in this way the referenced definition will usually be in a dictionary in the same XML document. </documentation>
</annotation>
</element>
<elementref="gml:indirectEntry">
<annotation>
<documentation>An identified reference to a remote entry in this dictionary, to be used when this entry should be identified to allow external references to this specific entry. </documentation>
<documentation>An entry in a dictionary of definitions. An instance of this type contains or refers to a definition object.
The number of definitions contained in this dictionaryEntry is restricted to one, but a DefinitionCollection or Dictionary that contains multiple definitions can be substituted if needed. Specialized descendents of this dictionaryEntry might be restricted in an application schema to allow only including specified types of definitions as valid entries in a dictionary. </documentation>
</annotation>
<sequenceminOccurs="0">
<elementref="gml:Definition">
<annotation>
<documentation>This element in a dictionary entry contains the actual definition. </documentation>
<documentation>A non-identified reference to a remote entry in this dictionary, to be used when this entry need not be identified to allow external references to this specific entry. The remote entry referenced will usually be in a dictionary in the same XML document. This element will usually be used in dictionaries that are inside of another dictionary. </documentation>
<documentation>An entry in a dictionary of definitions that contains a GML object which references a remote definition object. This entry is expected to be convenient in allowing multiple elements in one XML document to contain short (abbreviated XPointer) references, which are resolved to an external definition provided in a Dictionary element in the same XML document. Specialized descendents of this dictionaryEntry might be restricted in an application schema to allow only including specified types of definitions as valid entries in a dictionary. </documentation>
<documentation>A proxy entry in a dictionary of definitions. An element of this type contains a reference to a remote definition object. This entry is expected to be convenient in allowing multiple elements in one XML document to contain short (abbreviated XPointer) references, which are resolved to an external definition provided in a Dictionary element in the same XML document. </documentation>
</annotation>
<complexContent>
<extensionbase="gml:DefinitionType">
<sequence>
<elementref="gml:definitionRef">
<annotation>
<documentation>A reference to a remote entry in this dictionary, used when this dictionary entry is identified to allow external references to this specific entry. The remote entry referenced can be in a dictionary in the same or different XML document. </documentation>
<documentationxml:lang="en">The track of a moving object is a sequence of specialized timeslices that indicate the status of the object.</documentation>
<documentation>An abstract feature provides a set of common properties, including id, metaDataProperty, name and description inherited from AbstractGMLType, plus boundedBy. A concrete feature type must derive from this type and specify additional properties in an application schema. A feature must possess an identifying attribute ('id' - 'fid' has been deprecated).</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractGMLType">
<sequence>
<elementref="gml:boundedBy"minOccurs="0"/>
<elementref="gml:location"minOccurs="0">
<annotation>
<appinfo>deprecated</appinfo>
<documentation>deprecated in GML version 3.1</documentation>
</annotation>
</element>
<!-- additional properties must be specified in an application schema -->
<documentation>The members of the geometric aggregate can be specified either using the "standard" property or the array property style. It is also valid to use both the "standard" and the array property style in the same collection.
<sch:patternname="Check either href or content not both">
<sch:rulecontext="gml:multiGeometryProperty">
<sch:extendsrule="hrefOrContent"/>
</sch:rule>
</sch:pattern>
</appinfo>
<documentation>This property element either references a geometric aggregate via the XLink-attributes or contains the "multi geometry" element. multiGeometryProperty is the predefined property which can be used by GML Application Schemas whenever a GML Feature has a property with a value that is substitutable for _GeometricAggregate.</documentation>
<documentation>A property that has a geometric aggregate as its value domain can either be an appropriate geometry element encapsulated in an element of this type or an XLink reference to a remote geometry element (where remote includes geometry elements located elsewhere in the same document). Either the reference or the contained element must be given, but neither both nor none.</documentation>
<documentation>This attribute group includes the XLink attributes (see xlinks.xsd). XLink is used in GML to reference remote resources (including those elsewhere in the same document). A simple link element can be constructed by including a specific set of XLink attributes. The XML Linking Language (XLink) is currently a Proposed Recommendation of the World Wide Web Consortium. XLink allows elements to be inserted into XML documents so as to create sophisticated links between resources; such links can be used to reference remote properties.
A simple link element can be used to implement pointer functionality, and this functionality has been built into various GML 3 elements by including the gml:AssociationAttributeGroup.</documentation>
<documentation>The members of the geometric aggregate can be specified either using the "standard" property or the array property style. It is also valid to use both the "standard" and the array property style in the same collection.
<sch:patternname="Check either href or content not both">
<sch:rulecontext="gml:multiPointProperty">
<sch:extendsrule="hrefOrContent"/>
</sch:rule>
</sch:pattern>
</appinfo>
<documentation>This property element either references a point aggregate via the XLink-attributes or contains the "multi point" element. multiPointProperty is the predefined property which can be used by GML Application Schemas whenever a GML Feature has a property with a value that is substitutable for MultiPoint.</documentation>
<documentation>A property that has a collection of points as its value domain can either be an appropriate geometry element encapsulated in an element of this type or an XLink reference to a remote geometry element (where remote includes geometry elements located elsewhere in the same document). Either the reference or the contained element must be given, but neither both nor none.</documentation>
<documentation>This attribute group includes the XLink attributes (see xlinks.xsd). XLink is used in GML to reference remote resources (including those elsewhere in the same document). A simple link element can be constructed by including a specific set of XLink attributes. The XML Linking Language (XLink) is currently a Proposed Recommendation of the World Wide Web Consortium. XLink allows elements to be inserted into XML documents so as to create sophisticated links between resources; such links can be used to reference remote properties.
A simple link element can be used to implement pointer functionality, and this functionality has been built into various GML 3 elements by including the gml:AssociationAttributeGroup.</documentation>
<documentation>The members of the geometric aggregate can be specified either using the "standard" property or the array property style. It is also valid to use both the "standard" and the array property style in the same collection.
<sch:patternname="Check either href or content not both">
<sch:rulecontext="gml:multiCurveProperty">
<sch:extendsrule="hrefOrContent"/>
</sch:rule>
</sch:pattern>
</appinfo>
<documentation>This property element either references a curve aggregate via the XLink-attributes or contains the "multi curve" element. multiCurveProperty is the predefined property which can be used by GML Application Schemas whenever a GML Feature has a property with a value that is substitutable for MultiCurve.</documentation>
<documentation>A property that has a collection of curves as its value domain can either be an appropriate geometry element encapsulated in an element of this type or an XLink reference to a remote geometry element (where remote includes geometry elements located elsewhere in the same document). Either the reference or the contained element must be given, but neither both nor none.</documentation>
<documentation>This attribute group includes the XLink attributes (see xlinks.xsd). XLink is used in GML to reference remote resources (including those elsewhere in the same document). A simple link element can be constructed by including a specific set of XLink attributes. The XML Linking Language (XLink) is currently a Proposed Recommendation of the World Wide Web Consortium. XLink allows elements to be inserted into XML documents so as to create sophisticated links between resources; such links can be used to reference remote properties.
A simple link element can be used to implement pointer functionality, and this functionality has been built into various GML 3 elements by including the gml:AssociationAttributeGroup.</documentation>
<documentation>The members of the geometric aggregate can be specified either using the "standard" property or the array property style. It is also valid to use both the "standard" and the array property style in the same collection.
<sch:patternname="Check either href or content not both">
<sch:rulecontext="gml:multiSurfaceProperty">
<sch:extendsrule="hrefOrContent"/>
</sch:rule>
</sch:pattern>
</appinfo>
<documentation>This property element either references a surface aggregate via the XLink-attributes or contains the "multi surface" element. multiSurfaceProperty is the predefined property which can be used by GML Application Schemas whenever a GML Feature has a property with a value that is substitutable for MultiSurface.</documentation>
<documentation>A property that has a collection of surfaces as its value domain can either be an appropriate geometry element encapsulated in an element of this type or an XLink reference to a remote geometry element (where remote includes geometry elements located elsewhere in the same document). Either the reference or the contained element must be given, but neither both nor none.</documentation>
<documentation>This attribute group includes the XLink attributes (see xlinks.xsd). XLink is used in GML to reference remote resources (including those elsewhere in the same document). A simple link element can be constructed by including a specific set of XLink attributes. The XML Linking Language (XLink) is currently a Proposed Recommendation of the World Wide Web Consortium. XLink allows elements to be inserted into XML documents so as to create sophisticated links between resources; such links can be used to reference remote properties.
A simple link element can be used to implement pointer functionality, and this functionality has been built into various GML 3 elements by including the gml:AssociationAttributeGroup.</documentation>
<documentation>The members of the geometric aggregate can be specified either using the "standard" property or the array property style. It is also valid to use both the "standard" and the array property style in the same collection.
<sch:patternname="Check either href or content not both">
<sch:rulecontext="gml:multiSolidProperty">
<sch:extendsrule="hrefOrContent"/>
</sch:rule>
</sch:pattern>
</appinfo>
<documentation>This property element either references a solid aggregate via the XLink-attributes or contains the "multi solid" element. multiSolidProperty is the predefined property which can be used by GML Application Schemas whenever a GML Feature has a property with a value that is substitutable for MultiSolid.</documentation>
<documentation>A property that has a collection of solids as its value domain can either be an appropriate geometry element encapsulated in an element of this type or an XLink reference to a remote geometry element (where remote includes geometry elements located elsewhere in the same document). Either the reference or the contained element must be given, but neither both nor none.</documentation>
<documentation>This attribute group includes the XLink attributes (see xlinks.xsd). XLink is used in GML to reference remote resources (including those elsewhere in the same document). A simple link element can be constructed by including a specific set of XLink attributes. The XML Linking Language (XLink) is currently a Proposed Recommendation of the World Wide Web Consortium. XLink allows elements to be inserted into XML documents so as to create sophisticated links between resources; such links can be used to reference remote properties.
A simple link element can be used to implement pointer functionality, and this functionality has been built into various GML 3 elements by including the gml:AssociationAttributeGroup.</documentation>
<documentation>A MultiLineString is defined by one or more LineStrings, referenced through lineStringMember elements. Deprecated with GML version 3.0. Use MultiCurveType instead.</documentation>
<documentation>This type is deprecated with GML 3 and shall not be used. It is included for backwards compatibility with GML 2. Use MultiCurvePropertyType instead.
A property that has a collection of line strings as its value domain can either be an appropriate geometry element encapsulated in an element of this type or an XLink reference to a remote geometry element (where remote includes geometry elements located elsewhere in the same document). Either the reference or the contained element must be given, but neither both nor none.</documentation>
<documentation>This attribute group includes the XLink attributes (see xlinks.xsd). XLink is used in GML to reference remote resources (including those elsewhere in the same document). A simple link element can be constructed by including a specific set of XLink attributes. The XML Linking Language (XLink) is currently a Proposed Recommendation of the World Wide Web Consortium. XLink allows elements to be inserted into XML documents so as to create sophisticated links between resources; such links can be used to reference remote properties.
A simple link element can be used to implement pointer functionality, and this functionality has been built into various GML 3 elements by including the gml:AssociationAttributeGroup.</documentation>
<documentation>A MultiPolygon is defined by one or more Polygons, referenced through polygonMember elements. Deprecated with GML version 3.0. Use MultiSurfaceType instead.</documentation>
<documentation>This type is deprecated with GML 3 and shall not be used. It is included for backwards compatibility with GML 2. Use MultiSurfacePropertyType instead.
A property that has a collection of polygons as its value domain can either be an appropriate geometry element encapsulated in an element of this type or an XLink reference to a remote geometry element (where remote includes geometry elements located elsewhere in the same document). Either the reference or the contained element must be given, but neither both nor none.</documentation>
<documentation>This attribute group includes the XLink attributes (see xlinks.xsd). XLink is used in GML to reference remote resources (including those elsewhere in the same document). A simple link element can be constructed by including a specific set of XLink attributes. The XML Linking Language (XLink) is currently a Proposed Recommendation of the World Wide Web Consortium. XLink allows elements to be inserted into XML documents so as to create sophisticated links between resources; such links can be used to reference remote properties.
A simple link element can be used to implement pointer functionality, and this functionality has been built into various GML 3 elements by including the gml:AssociationAttributeGroup.</documentation>
<documentation>This property element contains a list of geometry elements. The order of the elements is significant and shall be preserved when processing the array.</documentation>
<documentation>This property element contains a list of points. The order of the elements is significant and shall be preserved when processing the array.</documentation>
<documentation>This property element contains a list of curves. The order of the elements is significant and shall be preserved when processing the array.</documentation>
<documentation>This property element either references a surface via the XLink-attributes or contains the surface element. A surface element is any element which is substitutable for "_Surface".</documentation>
<documentation>This property element contains a list of surfaces. The order of the elements is significant and shall be preserved when processing the array.</documentation>
<documentation>This property element either references a solid via the XLink-attributes or contains the solid element. A solid element is any element which is substitutable for "_Solid".</documentation>
<documentation>This property element contains a list of solids. The order of the elements is significant and shall be preserved when processing the array.</documentation>
</annotation>
</element>
<!-- some named geometry properties - for backward compatibility with GML2 -->
<sch:reporttest="not(@srsDimension) or @srsName">The presence of a dimension attribute implies the presence of the srsName attribute.</sch:report>
<sch:reporttest="not(@axisLabels) or @srsName">The presence of an axisLabels attribute implies the presence of the srsName attribute.</sch:report>
<sch:reporttest="not(@uomLabels) or @srsName">The presence of an uomLabels attribute implies the presence of the srsName attribute.</sch:report>
<sch:reporttest="(not(@uomLabels) and not(@axisLabels)) or (@uomLabels and @axisLabels)">The presence of an uomLabels attribute implies the presence of the axisLabels attribute and vice versa.</sch:report>
</sch:rule>
</sch:pattern>
<sch:patternname="Check Dimension">
<sch:ruleabstract="true"id="Count">
<sch:reporttest="not(@count) or @srsDimension">The presence of a count attribute implies the presence of the dimension attribute.</sch:report>
</sch:rule>
</sch:pattern>
</appinfo>
<documentation>Copyright (c) 2001-2005 OGC, All Rights Reserved.
For conditions, see OGC Software Notice http://www.opengeospatial.org/about/?page=ipr</documentation>
<documentation>Vector instances hold the compoents for a (usually spatial) vector within some coordinate reference system (CRS).
Since Vectors will often be included in larger objects that have references to CRS, the "srsName" attribute may be missing.
In this case, the CRS is implicitly assumed to take on the value of the containing object's CRS.
Note that this content model is the same as DirectPositionType, but is defined separately to reflect the distinct semantics, and to avoid validation problems. SJDC 2004-12-02</documentation>
<documentation>An abstraction of a surface to support the different levels of complexity. A surface is always a continuous region of a plane.</documentation>
<sch:patternname="Check either href or content not both">
<sch:rulecontext="gml:surfaceProperty">
<sch:extendsrule="hrefOrContent"/>
</sch:rule>
</sch:pattern>
</appinfo>
<documentation>This property element either references a surface via the XLink-attributes or contains the surface element. surfaceProperty is the predefined property which can be used by GML Application Schemas whenever a GML Feature has a property with a value that is substitutable for _Surface.</documentation>
<documentation>A property that has a surface as its value domain can either be an appropriate geometry element encapsulated in an element of this type or an XLink reference to a remote geometry element (where remote includes geometry elements located elsewhere in the same document). Either the reference or the contained element must be given, but neither both nor none.</documentation>
<documentation>This attribute group includes the XLink attributes (see xlinks.xsd). XLink is used in GML to reference remote resources (including those elsewhere in the same document). A simple link element can be constructed by including a specific set of XLink attributes. The XML Linking Language (XLink) is currently a Proposed Recommendation of the World Wide Web Consortium. XLink allows elements to be inserted into XML documents so as to create sophisticated links between resources; such links can be used to reference remote properties.
A simple link element can be used to implement pointer functionality, and this functionality has been built into various GML 3 elements by including the gml:AssociationAttributeGroup.</documentation>
<documentation>A container for an array of surfaces. The elements are always contained in the array property, referencing geometry elements or arrays of geometry elements is not supported.</documentation>
<documentation>A Polygon is a special surface that is defined by a single surface patch. The boundary of this patch is coplanar and the polygon uses planar interpolation in its interior. It is backwards compatible with the Polygon of GML 2, GM_Polygon of ISO 19107 is implemented by PolygonPatch.</documentation>
<documentation>A boundary of a surface consists of a number of rings. In the normal 2D case, one of these rings is distinguished as being the exterior boundary. In a general manifold this is not always possible, in which case all boundaries shall be listed as interior boundaries, and the exterior will be empty.</documentation>
<documentation>A boundary of a surface consists of a number of rings. The "interior" rings seperate the surface / surface patch from the area enclosed by the rings.</documentation>
<documentation>A LinearRing is defined by four or more coordinate tuples, with linear interpolation between them; the first and last coordinates must be coincident.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractRingType">
<sequence>
<choice>
<annotation>
<documentation>GML supports two different ways to specify the control points of a linear ring.
1. A sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that are only part of this ring, "pointProperty" elements contain a point that may be referenced from other geometry elements or reference another point defined outside of this ring (reuse of existing points).
2. The "posList" element allows for a compact way to specifiy the coordinates of the control points, if all control points are in the same coordinate reference systems and belong to this ring only. The number of direct positions in the list must be at least four.</documentation>
</annotation>
<choiceminOccurs="4"maxOccurs="unbounded">
<elementref="gml:pos"/>
<elementref="gml:pointProperty"/>
<elementref="gml:pointRep">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "pointProperty" instead. Included for backwards compatibility with GML 3.0.0.</documentation>
</annotation>
</element>
</choice>
<elementref="gml:posList"/>
<elementref="gml:coordinates">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "posList" instead.</documentation>
<documentation>This type is deprecated with GML 3 and shall not be used. It is included for backwards compatibility with GML 2. Use SurfacePropertyType instead.
A property that has a polygon as its value domain can either be an appropriate geometry element encapsulated in an element of this type or an XLink reference to a remote geometry element (where remote includes geometry elements located elsewhere in the same document). Either the reference or the contained element must be given, but neither both nor none.</documentation>
<documentation>This attribute group includes the XLink attributes (see xlinks.xsd). XLink is used in GML to reference remote resources (including those elsewhere in the same document). A simple link element can be constructed by including a specific set of XLink attributes. The XML Linking Language (XLink) is currently a Proposed Recommendation of the World Wide Web Consortium. XLink allows elements to be inserted into XML documents so as to create sophisticated links between resources; such links can be used to reference remote properties.
A simple link element can be used to implement pointer functionality, and this functionality has been built into various GML 3 elements by including the gml:AssociationAttributeGroup.</documentation>
<documentation>A CompositeCurve is defined by a sequence of (orientable) curves such that the each curve in the sequence terminates at the start point of the subsequent curve in the list.</documentation>
<documentation>This element references or contains one curve in the composite curve. The curves are contiguous, the collection of curves is ordered.
NOTE: This definition allows for a nested structure, i.e. a CompositeCurve may use, for example, another CompositeCurve as a curve member.</documentation>
<documentation>A CompositeSurface is defined by a set of orientable surfaces. A composite surface is geometry type with all the geometric properties of a (primitive) surface. Essentially, a composite surface is a collection of surfaces that join in pairs on common boundary curves and which, when considered as a whole, form a single surface.</documentation>
<documentation>This element references or contains one surface in the composite surface. The surfaces are contiguous.
NOTE: This definition allows for a nested structure, i.e. a CompositeSurface may use, for example, another CompositeSurface as a member.</documentation>
<documentation>A composite solid is a geometry type with all the geometric properties of a (primitive) solid.
Essentially, a composite solid is a collection of solids that join in pairs on common boundary surfaces and which, when considered as a whole, form a single solid.</documentation>
<documentation>A property that has a geometric complex as its value domain can either be an appropriate geometry element encapsulated in an element of this type or an XLink reference to a remote geometry element (where remote includes geometry elements located elsewhere in the same document). Either the reference or the contained element must be given, but neither both nor none.
NOTE: The allowed geometry elements contained in such a property (or referenced by it) have to be modelled by an XML Schema choice element since the composites inherit both from geometric complex *and* geometric primitive and are already part of the _GeometricPrimitive substitution group.</documentation>
<documentation>This attribute group includes the XLink attributes (see xlinks.xsd). XLink is used in GML to reference remote resources (including those elsewhere in the same document). A simple link element can be constructed by including a specific set of XLink attributes. The XML Linking Language (XLink) is currently a Proposed Recommendation of the World Wide Web Consortium. XLink allows elements to be inserted into XML documents so as to create sophisticated links between resources; such links can be used to reference remote properties.
A simple link element can be used to implement pointer functionality, and this functionality has been built into various GML 3 elements by including the gml:AssociationAttributeGroup.</documentation>
<documentation>Curve is a 1-dimensional primitive. Curves are continuous, connected, and have a measurable length in terms of the coordinate system.
A curve is composed of one or more curve segments. Each curve segment within a curve may be defined using a different interpolation method. The curve segments are connected to one another, with the end point of each segment except the last being the start point of the next segment in the segment list.
The orientation of the curve is positive.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractCurveType">
<sequence>
<elementref="gml:segments">
<annotation>
<documentation>This element encapsulates the segments of the curve.</documentation>
<sch:patternname="Check either href or content not both">
<sch:rulecontext="gml:baseCurve">
<sch:extendsrule="hrefOrContent"/>
</sch:rule>
</sch:pattern>
</appinfo>
<documentation>This property element either references a curve via the XLink-attributes or contains the curve element. A curve element is any element which is substitutable for "_Curve".</documentation>
<documentation>OrientableCurve consists of a curve and an orientation. If the orientation is "+", then the OrientableCurve is identical to the baseCurve. If the orientation is "-", then the OrientableCurve is related to another _Curve with a parameterization that reverses the sense of the curve traversal.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractCurveType">
<sequence>
<elementref="gml:baseCurve">
<annotation>
<documentation>References or contains the base curve (positive orientation).
NOTE: This definition allows for a nested structure, i.e. an OrientableCurve may use another OrientableCurve as its base curve.</documentation>
<documentation>If the orientation is "+", then the OrientableCurve is identical to the baseCurve. If the orientation is "-", then the OrientableCurve is related to another _Curve with a parameterization that reverses the sense of the curve traversal. "+" is the default value.</documentation>
<documentation>The "_CurveSegment" element is the abstract head of the substituition group for all curve segment elements, i.e. continuous segments of the same interpolation mechanism.</documentation>
<documentation>The attribute "numDerivativesAtStart" specifies the type of continuity between this curve segment and its predecessor. If this is the first curve segment in the curve, one of these values, as appropriate, is ignored. The default value of "0" means simple continuity, which is a mandatory minimum level of continuity. This level is referred to as "C 0 " in mathematical texts. A value of 1 means that the function and its first derivative are continuous at the appropriate end point: "C 1 " continuity. A value of "n" for any integer means the function and its first n derivatives are continuous: "C n " continuity.
NOTE: Use of these values is only appropriate when the basic curve definition is an underdetermined system. For example, line string segments cannot support continuity above C 0 , since there is no spare control parameter to adjust the incoming angle at the end points of the segment. Spline functions on the other hand often have extra degrees of freedom on end segments that allow them to adjust the values of the derivatives to support C 1 or higher continuity.</documentation>
<documentation>The attribute "numDerivativesAtEnd" specifies the type of continuity between this curve segment and its successor. If this is the last curve segment in the curve, one of these values, as appropriate, is ignored. The default value of "0" means simple continuity, which is a mandatory minimum level of continuity. This level is referred to as "C 0 " in mathematical texts. A value of 1 means that the function and its first derivative are continuous at the appropriate end point: "C 1 " continuity. A value of "n" for any integer means the function and its first n derivatives are continuous: "C n " continuity.
NOTE: Use of these values is only appropriate when the basic curve definition is an underdetermined system. For example, line string segments cannot support continuity above C 0 , since there is no spare control parameter to adjust the incoming angle at the end points of the segment. Spline functions on the other hand often have extra degrees of freedom on end segments that allow them to adjust the values of the derivatives to support C 1 or higher continuity.</documentation>
<documentation>The attribute "numDerivativesInterior" specifies the type of continuity that is guaranteed interior to the curve. The default value of "0" means simple continuity, which is a mandatory minimum level of continuity. This level is referred to as "C 0 " in mathematical texts. A value of 1 means that the function and its first derivative are continuous at the appropriate end point: "C 1 " continuity. A value of "n" for any integer means the function and its first n derivatives are continuous: "C n " continuity.
NOTE: Use of these values is only appropriate when the basic curve definition is an underdetermined system. For example, line string segments cannot support continuity above C 0 , since there is no spare control parameter to adjust the incoming angle at the end points of the segment. Spline functions on the other hand often have extra degrees of freedom on end segments that allow them to adjust the values of the derivatives to support C 1 or higher continuity.</documentation>
<documentation>This property element contains a list of curve segments. The order of the elements is significant and shall be preserved when processing the array.</documentation>
<documentation>A LineStringSegment is a curve segment that is defined by two or more coordinate tuples, with linear interpolation between them.
Note: LineStringSegment implements GM_LineString of ISO 19107.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractCurveSegmentType">
<sequence>
<choice>
<annotation>
<documentation>GML supports two different ways to specify the control points of a curve segment.
1. A sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that are only part of this curve segment, "pointProperty" elements contain a point that may be referenced from other geometry elements or reference another point defined outside of this curve segment (reuse of existing points).
2. The "posList" element allows for a compact way to specifiy the coordinates of the control points, if all control points are in the same coordinate reference systems and belong to this curve segment only. The number of direct positions in the list must be at least two.</documentation>
</annotation>
<choiceminOccurs="2"maxOccurs="unbounded">
<elementref="gml:pos"/>
<elementref="gml:pointProperty"/>
<elementref="gml:pointRep">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "pointProperty" instead. Included for backwards compatibility with GML 3.0.0.</documentation>
</annotation>
</element>
</choice>
<elementref="gml:posList"/>
<elementref="gml:coordinates">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "posList" instead.</documentation>
<documentation>The attribute "interpolation" specifies the curve interpolation mechanism used for this segment. This mechanism
uses the control points and control parameters to determine the position of this curve segment. For a LineStringSegment the interpolation is fixed as "linear".</documentation>
</annotation>
</attribute>
</extension>
</complexContent>
</complexType>
<!-- =========== global element in "_CurveSegment" substitution group ================ -->
<documentation>An ArcString is a curve segment that uses three-point circular arc interpolation.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractCurveSegmentType">
<sequence>
<choice>
<annotation>
<documentation>GML supports two different ways to specify the control points of a curve segment.
1. A sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that are only part of this curve segment, "pointProperty" elements contain a point that may be referenced from other geometry elements or reference another point defined outside of this curve segment (reuse of existing points).
2. The "posList" element allows for a compact way to specifiy the coordinates of the control points, if all control points are in the same coordinate reference systems and belong to this curve segment only. The number of direct positions in the list must be at least three.</documentation>
</annotation>
<choiceminOccurs="3"maxOccurs="unbounded">
<elementref="gml:pos"/>
<elementref="gml:pointProperty"/>
<elementref="gml:pointRep">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "pointProperty" instead. Included for backwards compatibility with GML 3.0.0.</documentation>
</annotation>
</element>
</choice>
<elementref="gml:posList"/>
<elementref="gml:coordinates">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "posList" instead.</documentation>
<documentation>The attribute "interpolation" specifies the curve interpolation mechanism used for this segment. This mechanism
uses the control points and control parameters to determine the position of this curve segment. For an ArcString the interpolation is fixed as "circularArc3Points".</documentation>
<documentation>The number of arcs in the arc string can be explicitly stated in this attribute. The number of control points in the arc string must be 2 * numArc + 1.</documentation>
</annotation>
</attribute>
</extension>
</complexContent>
</complexType>
<!-- =========== global element in "_CurveSegment" substitution group ================ -->
<documentation>An Arc is an arc string with only one arc unit, i.e. three control points.</documentation>
</annotation>
<complexContent>
<restrictionbase="gml:ArcStringType">
<sequence>
<choice>
<annotation>
<documentation>GML supports two different ways to specify the control points of a curve segment.
1. A sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that are only part of this curve segment, "pointProperty" elements contain a point that may be referenced from other geometry elements or reference another point defined outside of this curve segment (reuse of existing points).
2. The "posList" element allows for a compact way to specifiy the coordinates of the control points, if all control points are in the same coordinate reference systems and belong to this curve segment only. The number of direct positions in the list must be three.</documentation>
</annotation>
<choiceminOccurs="3"maxOccurs="3">
<elementref="gml:pos"/>
<elementref="gml:pointProperty"/>
<elementref="gml:pointRep">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "pointProperty" instead. Included for backwards compatibility with GML 3.0.0.</documentation>
</annotation>
</element>
</choice>
<elementref="gml:posList"/>
<elementref="gml:coordinates">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "posList" instead.</documentation>
<documentation>A Circle is an arc whose ends coincide to form a simple closed loop. The "start" and "end" bearing are equal and shall be the bearing for the first controlPoint listed. The three control points must be distinct non-co-linear points for the Circle to be unambiguously defined. The arc is simply extended past the third control point until the first control point is encountered.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:ArcType"/>
</complexContent>
</complexType>
<!-- =========== global element in "_CurveSegment" substitution group ================ -->
<documentation>This variant of the arc computes the mid points of the arcs instead of storing the coordinates directly. The control point sequence consists of the start and end points of each arc plus the bulge.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractCurveSegmentType">
<sequence>
<choice>
<annotation>
<documentation>GML supports two different ways to specify the control points of a curve segment.
1. A sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that are only part of this curve segment, "pointProperty" elements contain a point that may be referenced from other geometry elements or reference another point defined outside of this curve segment (reuse of existing points).
2. The "posList" element allows for a compact way to specifiy the coordinates of the control points, if all control points are in the same coordinate reference systems and belong to this curve segment only. The number of direct positions in the list must be at least two.</documentation>
</annotation>
<choiceminOccurs="2"maxOccurs="unbounded">
<elementref="gml:pos"/>
<elementref="gml:pointProperty"/>
<elementref="gml:pointRep">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "pointProperty" instead. Included for backwards compatibility with GML 3.0.0.</documentation>
</annotation>
</element>
</choice>
<elementref="gml:posList"/>
<elementref="gml:coordinates">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "posList" instead.</documentation>
<documentation>The bulge controls the offset of each arc's midpoint. The "bulge" is the real number multiplier for the normal that determines the offset direction of the midpoint of each arc. The length of the bulge sequence is exactly 1 less than the length of the control point array, since a bulge is needed for each pair of adjacent points in the control point array. The bulge is not given by a distance, since it is simply a multiplier for the normal.
The midpoint of the resulting arc is given by: midPoint = ((startPoint + endPoint)/2.0) + bulge*normal</documentation>
<documentation>The attribute "normal" is a vector normal (perpendicular) to the chord of the arc, the line joining the first and last
point of the arc. In a 2D coordinate system, there are only two possible directions for the normal, and it is often given as a signed real, indicating its length, with a positive sign indicating a left turn angle from the chord line, and a negative sign indicating a right turn from the chord. In 3D, the normal determines the plane of the arc, along with the start and endPoint of the arc.
The normal is usually a unit vector, but this is not absolutely necessary. If the normal is a zero vector, the geometric object becomes equivalent to the straight line between the two end points. The length of the normal sequence is exactly the same as for the bulge sequence, 1 less than the control point sequence length.</documentation>
<documentation>The attribute "interpolation" specifies the curve interpolation mechanism used for this segment. This mechanism
uses the control points and control parameters to determine the position of this curve segment. For an ArcStringByBulge the interpolation is fixed as "circularArc2PointWithBulge".</documentation>
<documentation>The number of arcs in the arc string can be explicitly stated in this attribute. The number of control points in the arc string must be numArc + 1.</documentation>
</annotation>
</attribute>
</extension>
</complexContent>
</complexType>
<!-- =========== global element in "_CurveSegment" substitution group ================ -->
<documentation>An ArcByBulge is an arc string with only one arc unit, i.e. two control points and one bulge.</documentation>
</annotation>
<complexContent>
<restrictionbase="gml:ArcStringByBulgeType">
<sequence>
<choice>
<annotation>
<documentation>GML supports two different ways to specify the control points of a curve segment.
1. A sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that are only part of this curve segment, "pointProperty" elements contain a point that may be referenced from other geometry elements or reference another point defined outside of this curve segment (reuse of existing points).
2. The "posList" element allows for a compact way to specifiy the coordinates of the control points, if all control points are in the same coordinate reference systems and belong to this curve segment only. The number of direct positions in the list must be two.</documentation>
</annotation>
<choiceminOccurs="2"maxOccurs="2">
<elementref="gml:pos"/>
<elementref="gml:pointProperty"/>
<elementref="gml:pointRep">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "pointProperty" instead. Included for backwards compatibility with GML 3.0.0.</documentation>
</annotation>
</element>
</choice>
<elementref="gml:posList"/>
<elementref="gml:coordinates">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "posList" instead.</documentation>
</annotation>
</element>
</choice>
<elementname="bulge"type="double">
<annotation>
<documentation>The bulge controls the offset of each arc's midpoint. The "bulge" is the real number multiplier for the normal that determines the offset direction of the midpoint of each arc. The length of the bulge sequence is exactly 1 less than the length of the control point array, since a bulge is needed for each pair of adjacent points in the control point array. The bulge is not given by a distance, since it is simply a multiplier for the normal.
The midpoint of the resulting arc is given by: midPoint = ((startPoint + endPoint)/2.0) + bulge*normal</documentation>
</annotation>
</element>
<elementname="normal"type="gml:VectorType">
<annotation>
<documentation>The attribute "normal" is a vector normal (perpendicular) to the chord of the arc, the line joining the first and last
point of the arc. In a 2D coordinate system, there are only two possible directions for the normal, and it is often given as a signed real, indicating its length, with a positive sign indicating a left turn angle from the chord line, and a negative sign indicating a right turn from the chord. In 3D, the normal determines the plane of the arc, along with the start and endPoint of the arc.
The normal is usually a unit vector, but this is not absolutely necessary. If the normal is a zero vector, the geometric object becomes equivalent to the straight line between the two end points. The length of the normal sequence is exactly the same as for the bulge sequence, 1 less than the control point sequence length.</documentation>
<documentation>This variant of the arc requires that the points on the arc have to be computed instead of storing the coordinates directly. The control point is the center point of the arc plus the radius and the bearing at start and end. This represenation can be used only in 2D.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractCurveSegmentType">
<sequence>
<choice>
<annotation>
<documentation>GML supports two different ways to specify the control points of a curve segment.
1. A "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) element. The "pos" element contains a center point that is only part of this curve segment, a "pointProperty" element contains a point that may be referenced from other geometry elements or reference another point defined outside of this curve segment (reuse of existing points).
2. The "posList" element can be used to specifiy the coordinates of the center point, too. The number of direct positions in the list must be one.</documentation>
</annotation>
<choice>
<elementref="gml:pos"/>
<elementref="gml:pointProperty"/>
<elementref="gml:pointRep">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "pointProperty" instead. Included for backwards compatibility with GML 3.0.0.</documentation>
</annotation>
</element>
</choice>
<elementref="gml:posList"/>
<elementref="gml:coordinates">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "posList" instead.</documentation>
</annotation>
</element>
</choice>
<elementname="radius"type="gml:LengthType">
<annotation>
<documentation>The radius of the arc.</documentation>
<documentation>The attribute "interpolation" specifies the curve interpolation mechanism used for this segment. This mechanism
uses the control points and control parameters to determine the position of this curve segment. For an ArcByCenterPoint the interpolation is fixed as "circularArcCenterPointWithRadius".</documentation>
<documentation>A CircleByCenterPoint is an ArcByCenterPoint with identical start and end angle to form a full circle. Again, this represenation can be used only in 2D.</documentation>
<documentation>Cubic splines are similar to line strings in that they are a sequence of segments each with its own defining function. A cubic spline uses the control points and a set of derivative parameters to define a piecewise 3rd degree polynomial interpolation. Unlike line-strings, the parameterization by arc length is not necessarily still a polynomial.
The function describing the curve must be C2, that is, have a continuous 1st and 2nd derivative at all points, and pass through the controlPoints in the order given. Between the control points, the curve segment is defined by a cubic polynomial. At each control point, the polynomial changes in such a manner that the 1st and 2nd derivative vectors are the same from either side. The control parameters record must contain vectorAtStart, and vectorAtEnd which are the unit tangent vectors at controlPoint[1] and controlPoint[n] where n = controlPoint.count.
Note: only the direction of the vectors is relevant, not their length.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractCurveSegmentType">
<sequence>
<choice>
<annotation>
<documentation>GML supports two different ways to specify the control points of a curve segment.
1. A sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that are only part of this curve segment, "pointProperty" elements contain a point that may be referenced from other geometry elements or reference another point defined outside of this curve segment (reuse of existing points).
2. The "posList" element allows for a compact way to specifiy the coordinates of the control points, if all control points are in the same coordinate reference systems and belong to this curve segment only. The number of direct positions in the list must be at least three.</documentation>
</annotation>
<choiceminOccurs="2"maxOccurs="unbounded">
<elementref="gml:pos"/>
<elementref="gml:pointProperty"/>
<elementref="gml:pointRep">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "pointProperty" instead. Included for backwards compatibility with GML 3.0.0.</documentation>
</annotation>
</element>
</choice>
<elementref="gml:posList"/>
<elementref="gml:coordinates">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "posList" instead.</documentation>
<documentation>The attribute "interpolation" specifies the curve interpolation mechanism used for this segment. This mechanism
uses the control points and control parameters to determine the position of this curve segment. For a CubicSpline the interpolation is fixed as "cubicSpline".</documentation>
</annotation>
</attribute>
<attributename="degree"type="integer"fixed="3">
<annotation>
<documentation>The degree for a cubic spline is "3".</documentation>
<documentation>A knot is a breakpoint on a piecewise spline curve.</documentation>
</annotation>
<sequence>
<elementname="value"type="double">
<annotation>
<documentation>The property "value" is the value of the parameter at the knot of the spline. The sequence of knots shall be a non-decreasing sequence. That is, each knot's value in the sequence shall be equal to or greater than the previous knot's value. The use of equal consecutive knots is normally handled using the multiplicity.</documentation>
<documentation>The property "multiplicity" is the multiplicity of this knot used in the definition of the spline (with the same weight).</documentation>
</annotation>
</element>
<elementname="weight"type="double">
<annotation>
<documentation>The property "weight" is the value of the averaging weight used for this knot of the spline.</documentation>
<documentation>A B-Spline is a piecewise parametric polynomial or rational curve described in terms of control points and basis functions. Knots are breakpoints on the curve that connect its pieces. They are given as a non-decreasing sequence of real numbers. If the weights in the knots are equal then it is a polynomial spline. The degree is the algebraic degree of the basis functions.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractCurveSegmentType">
<sequence>
<choice>
<annotation>
<documentation>GML supports two different ways to specify the control points of a curve segment.
1. A sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that are only part of this curve segment, "pointProperty" elements contain a point that may be referenced from other geometry elements or reference another point defined outside of this curve segment (reuse of existing points).
2. The "posList" element allows for a compact way to specifiy the coordinates of the control points, if all control points are in the same coordinate reference systems and belong to this curve segment only.</documentation>
</annotation>
<choiceminOccurs="0"maxOccurs="unbounded">
<elementref="gml:pos"/>
<elementref="gml:pointProperty"/>
<elementref="gml:pointRep">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "pointProperty" instead. Included for backwards compatibility with GML 3.0.0.</documentation>
</annotation>
</element>
</choice>
<elementref="gml:posList"/>
<elementref="gml:coordinates">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "posList" instead.</documentation>
</annotation>
</element>
</choice>
<elementname="degree"type="nonNegativeInteger">
<annotation>
<documentation>The attribute "degree" shall be the degree of the polynomial used for interpolation in this spline.</documentation>
<documentation>The attribute "interpolation" specifies the curve interpolation mechanism used for this segment. This mechanism
uses the control points and control parameters to determine the position of this curve segment. For a BSpline the interpolation can be either "polynomialSpline" or "rationalSpline", default is "polynomialSpline".</documentation>
<documentation>Bezier curves are polynomial splines that use Bezier or Bernstein polynomials for interpolation purposes. It is a special case of the B-Spline curve with two knots.</documentation>
</annotation>
<complexContent>
<restrictionbase="gml:BSplineType">
<sequence>
<choice>
<annotation>
<documentation>GML supports two different ways to specify the control points of a curve segment.
1. A sequence of "pos" (DirectPositionType) or "pointProperty" (PointPropertyType) elements. "pos" elements are control points that are only part of this curve segment, "pointProperty" elements contain a point that may be referenced from other geometry elements or reference another point defined outside of this curve segment (reuse of existing points).
2. The "posList" element allows for a compact way to specifiy the coordinates of the control points, if all control points are in the same coordinate reference systems and belong to this curve segment only.</documentation>
</annotation>
<choiceminOccurs="0"maxOccurs="unbounded">
<elementref="gml:pos"/>
<elementref="gml:pointProperty"/>
<elementref="gml:pointRep">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "pointProperty" instead. Included for backwards compatibility with GML 3.0.0.</documentation>
</annotation>
</element>
</choice>
<elementref="gml:posList"/>
<elementref="gml:coordinates">
<annotation>
<documentation>Deprecated with GML version 3.1.0. Use "posList" instead.</documentation>
</annotation>
</element>
</choice>
<elementname="degree"type="nonNegativeInteger">
<annotation>
<documentation>The attribute "degree" shall be the degree of the polynomial used for interpolation in this spline.</documentation>
<documentation>The attribute "interpolation" specifies the curve interpolation mechanism used for this segment. This mechanism
uses the control points and control parameters to determine the position of this curve segment. For a Bezier the interpolation is fixed as "polynomialSpline".</documentation>
<documentation>A Surface is a 2-dimensional primitive and is composed of one or more surface patches. The surface patches are connected to one another.
The orientation of the surface is positive ("up"). The orientation of a surface chooses an "up" direction through the choice of the upward normal, which, if the surface is not a cycle, is the side of the surface from which the exterior boundary appears counterclockwise. Reversal of the surface orientation reverses the curve orientation of each boundary component, and interchanges the conceptual "up" and "down" direction of the surface. If the surface is the boundary of a solid, the "up" direction is usually outward. For closed surfaces, which have no boundary, the up direction is that of the surface patches, which must be consistent with one another. Its included surface patches describe the interior structure of the Surface.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractSurfaceType">
<sequence>
<elementref="gml:patches">
<annotation>
<documentation>This element encapsulates the patches of the surface.</documentation>
<sch:patternname="Check either href or content not both">
<sch:rulecontext="gml:baseSurface">
<sch:extendsrule="hrefOrContent"/>
</sch:rule>
</sch:pattern>
</appinfo>
<documentation>This property element either references a surface via the XLink-attributes or contains the surface element. A surface element is any element which is substitutable for "_Surface".</documentation>
<documentation>OrientableSurface consists of a surface and an orientation. If the orientation is "+", then the OrientableSurface is identical to the baseSurface. If the orientation is "-", then the OrientableSurface is a reference to a Surface with an up-normal that reverses the direction for this OrientableSurface, the sense of "the top of the surface".</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractSurfaceType">
<sequence>
<elementref="gml:baseSurface">
<annotation>
<documentation>References or contains the base surface (positive orientation).</documentation>
<documentation>If the orientation is "+", then the OrientableSurface is identical to the baseSurface. If the orientation is "-", then the OrientableSurface is a reference to a Surface with an up-normal that reverses the direction for this OrientableSurface, the sense of "the top of the surface". "+" is the default value.</documentation>
<documentation>The "_SurfacePatch" element is the abstract head of the substituition group for all surface pach elements describing a continuous portion of a surface.</documentation>
<documentation>This property element contains a list of surface patches. The order of the elements is significant and shall be preserved when processing the array.</documentation>
<documentation>A PolygonPatch is a surface patch that is defined by a set of boundary curves and an underlying surface to which these curves adhere. The curves are coplanar and the polygon uses planar interpolation in its interior. Implements GM_Polygon of ISO 19107.</documentation>
<documentation>The attribute "interpolation" specifies the interpolation mechanism used for this surface patch. Currently only planar surface patches are defined in GML 3, the attribute is fixed to "planar", i.e. the interpolation method shall return points on a single plane. The boundary of the patch shall be contained within that plane.</documentation>
<documentation>Represents a triangle as a surface with an outer boundary consisting of a linear ring. Note that this is a polygon (subtype) with no inner boundaries. The number of points in the linear ring must be four.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractSurfacePatchType">
<sequence>
<elementref="gml:exterior">
<annotation>
<documentation>Constraint: The Ring shall be a LinearRing and must form a triangle, the first and the last position must be co-incident.</documentation>
<documentation>The attribute "interpolation" specifies the interpolation mechanism used for this surface patch. Currently only planar surface patches are defined in GML 3, the attribute is fixed to "planar", i.e. the interpolation method shall return points on a single plane. The boundary of the patch shall be contained within that plane.</documentation>
<documentation>Represents a rectangle as a surface with an outer boundary consisting of a linear ring. Note that this is a polygon (subtype) with no inner boundaries. The number of points in the linear ring must be five.</documentation>
</annotation>
<complexContent>
<extensionbase="gml:AbstractSurfacePatchType">
<sequence>
<elementref="gml:exterior">
<annotation>
<documentation>Constraint: The Ring shall be a LinearRing and must form a rectangle; the first and the last position must be co-incident.</documentation>
<documentation>The attribute "interpolation" specifies the interpolation mechanism used for this surface patch. Currently only planar surface patches are defined in GML 3, the attribute is fixed to "planar", i.e. the interpolation method shall return points on a single plane. The boundary of the patch shall be contained within that plane.</documentation>
<documentation>This property element either references a curve via the XLink-attributes or contains the curve element. A curve element is any element which is substitutable for "_Curve".</documentation>
<documentation>A Ring is used to represent a single connected component of a surface boundary. It consists of a sequence of curves connected in a cycle (an object whose boundary is empty).
A Ring is structurally similar to a composite curve in that the endPoint of each curve in the sequence is the startPoint of the next curve in the Sequence. Since the sequence is circular, there is no exception to this rule. Each ring, like all boundaries, is a cycle and each ring is simple.
NOTE: Even though each Ring is simple, the boundary need not be simple. The easiest case of this is where one of the interior rings of a surface is tangent to its exterior ring.</documentation>
<documentation>This element references or contains one curve in the composite curve. The curves are contiguous, the collection of curves is ordered.
NOTE: This definition allows for a nested structure, i.e. a CompositeCurve may use, for example, another CompositeCurve as a curve member.</documentation>
<sch:patternname="Check either href or content not both">
<sch:rulecontext="gml:solidProperty">
<sch:extendsrule="hrefOrContent"/>
</sch:rule>
</sch:pattern>
</appinfo>
<documentation>This property element either references a solid via the XLink-attributes or contains the solid element. solidProperty is the predefined property which can be used by GML Application Schemas whenever a GML Feature has a property with a value that is substitutable for _Solid.</documentation>
<documentation>A property that has a solid as its value domain can either be an appropriate geometry element encapsulated in an element of this type or an XLink reference to a remote geometry element (where remote includes geometry elements located elsewhere in the same document). Either the reference or the contained element must be given, but neither both nor none.</documentation>
<documentation>This attribute group includes the XLink attributes (see xlinks.xsd). XLink is used in GML to reference remote resources (including those elsewhere in the same document). A simple link element can be constructed by including a specific set of XLink attributes. The XML Linking Language (XLink) is currently a Proposed Recommendation of the World Wide Web Consortium. XLink allows elements to be inserted into XML documents so as to create sophisticated links between resources; such links can be used to reference remote properties.
A simple link element can be used to implement pointer functionality, and this functionality has been built into various GML 3 elements by including the gml:AssociationAttributeGroup.</documentation>
<documentation>A container for an array of solids. The elements are always contained in the array property, referencing geometry elements or arrays of geometry elements is not supported.</documentation>
<documentation>A solid is the basis for 3-dimensional geometry. The extent of a solid is defined by the boundary surfaces (shells). A shell is represented by a composite surface, where every shell is used to represent a single connected component of the boundary of a solid. It consists of a composite surface (a list of orientable surfaces) connected in a topological cycle (an object whose boundary is empty). Unlike a Ring, a Shell's elements have no natural sort order. Like Rings, Shells are simple.</documentation>
<sch:patternname="Check either href or content not both">
<sch:rulecontext="gml:exterior">
<sch:extendsrule="hrefOrContent"/>
</sch:rule>
</sch:pattern>
</appinfo>
<documentation>Boundaries of solids are similar to surface boundaries. In normal 3-dimensional Euclidean space, one (composite) surface is distinguished as the exterior. In the more general case, this is not always possible.</documentation>
<documentation>Defines allowed values for the knots` type. Uniform knots implies that all knots are of multiplicity 1 and they differ by a positive constant from the preceding knot. Knots are quasi-uniform iff they are of multiplicity (degree + 1) at the ends, of multiplicity 1 elsewhere, and they differ by a positive constant from the preceding knot.</documentation>
<sch:patternname="Check either href or content not both">
<sch:ruleabstract="true"id="hrefOrContent">
<sch:reporttest="@xlink:href and (*|text())">Property element may not carry both a reference to an object and contain an object.</sch:report>
<sch:asserttest="@xlink:href | (*|text())">Property element must either carry a reference to an object or contain an object.</sch:assert>
</sch:rule>
</sch:pattern>
</appinfo>
<documentation>GML base schema for GML 3
Components to support the GML encoding model.
The abstract Schematron rules can be used by any schema that includes gmlBase.
Copyright (c) 2001-2005 OGC, All Rights Reserved. For conditions, see OGC Software Notice http://www.opengeospatial.org/about/?page=ipr</documentation>
<!-- =========== Abstract "Object" is "anyType" ============= -->
<!-- ===== Global element at the head of the "Object" substitution group ======== -->
<elementname="_Object"abstract="true">
<annotation>
<documentation>This abstract element is the head of a substitutionGroup hierararchy which may contain either simpleContent or complexContent elements. It is used to assert the model position of "class" elements declared in other GML schemas.</documentation>
<documentation>Global element which acts as the head of a substitution group that may include any element which is a GML feature, object, geometry or complex value</documentation>
<documentation>Multiple names may be provided. These will often be distinguished by being assigned by different authorities, as indicated by the value of the codeSpace attribute. In an instance document there will usually only be one name per authority.</documentation>
<documentation>A non-abstract generic collection type that can be used as a document element for a collection of any GML types - Geometries, Topologies, Features ...
FeatureCollections may only contain Features. GeometryCollections may only contain Geometrys. Bags are less constrained they must contain objects that are substitutable for gml:_Object. This may mix several levels, including Features, Definitions, Dictionaries, Geometries etc.
The content model would ideally be
member 0..*
members 0..1
member 0..*
for maximum flexibility in building a collection from both homogeneous and distinct components:
included "member" elements each contain a single Object
an included "members" element contains a set of Objects
However, this is non-deterministic, thus prohibited by XSD.</documentation>
<documentation>A non-abstract generic collection type that can be used as a document element for a homogeneous collection of any GML types - Geometries, Topologies, Features ...</documentation>
<documentation>Concrete element in the _MetaData substitution group, which permits any well-formed XML content. Intended to act as a container for metadata defined in external schemas, for which it is not possible to add the concrete components to the GML _MetaData substitution group directly. Deprecated with GML version 3.1.0.</documentation>
<documentation>A pattern or base for derived types used to specify complex types corresponding to an unspecified UML association - either composition or aggregation. Restricts the cardinality of Objects contained in the association to a maximum of one. An instance of this type can contain an element representing an Object, or serve as a pointer to a remote Object.
Descendents of this type can be restricted in an application schema to
* allow only specified classes as valid participants in the aggregation
* allow only association by reference (i.e. empty the content model) or by value (i.e. remove the xlinks).
When used for association by reference, the value of the gml:remoteSchema attribute can be used to locate a schema fragment that constrains the target instance.
In many cases it is desirable to impose the constraint prohibiting the occurence of both reference and value in the same instance, as that would be ambiguous. This is accomplished by adding a directive in the annotation element of the element declaration. This directive can be in the form of normative prose, or can use a Schematron pattern to automatically constrain co-occurrence - see the declaration for _strictAssociation below.
If co-occurence is not prohibited, then both a link and content may be present. If this occurs in an instance, then the rule for interpretation is that the instance found by traversing the href provides the normative value of the property, and should be used when possible. The value(s) included as content may be used if the remote instance cannot be resolved. This may be considered to be a "cached" version of the value(s).</documentation>
<documentation>A pattern or base for derived types used to specify complex types corresponding to a UML aggregation association. An instance of this type serves as a pointer to a remote Object.</documentation>
<documentation>A base for derived types used to specify complex types containing an array of objects, by unspecified UML association - either composition or aggregation. An instance of this type contains elements representing Objects.
Ideally this type would be derived by extension of AssociationType.
However, this leads to a non-deterministic content model, since both the base and the extension have minOccurs="0", and is thus prohibited in XML Schema.</documentation>
<documentation>Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods. This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.</documentation>
<documentation>Reference to an XML Schema fragment that specifies the content model of the propertys value. This is in conformance with the XML Schema Section 4.14 Referencing Schemas from Elsewhere.</documentation>
<documentation>Attribute group used to enable property elements to refer to their value remotely. It contains the simple link components from xlinks.xsd, with all members optional, and the remoteSchema attribute, which is also optional. These attributes can be attached to any element, thus allowing it to act as a pointer. The 'remoteSchema' attribute allows an element that carries link attributes to indicate that the element is declared in a remote schema rather than by the schema that constrains the current document instance.</documentation>
<documentation>Label for the object, normally a descriptive name. An object may have several names, typically assigned by different authorities. The authority for a name is indicated by the value of its (optional) codeSpace attribute. The name may or may not be unique, as determined by the rules of the organization responsible for the codeSpace.</documentation>
<documentation>This type is available wherever there is a need for a "text" type property. It is of string type, so the text can be included inline, but the value can also be referenced remotely via xlinks from the AssociationAttributeGroup. If the remote reference is present, then the value obtained by traversing the link should be used, and the string content of the element can be used for an annotation.</documentation>
<documentation>An unrectified grid, which is a network composed of two or more sets of equally spaced parallel lines in which the members of each set intersect the members of the other sets at right angles.</documentation>
<documentation>Provides grid coordinate values for the diametrically opposed corners of an envelope that bounds a section of grid. The value of a single coordinate is the number of offsets from the origin of the grid in the direction of a specific axis.</documentation>
<documentation>Extends the units.xsd and basicTypes.xsd schemas with types for recording measures using specific types of units, especially the measures and units needed for coordinate reference systems and coordinate operations. The specific unit types encoded are length, angle, scale factor, time, area, volume, speed, and grid length. This schema allows angle values to be recorded as single numbers or in degree-minute-second format.
Copyright (c) 2002-2005 OGC, All Rights Reserved. For conditions, see OGC Software Notice http://www.opengeospatial.org/about/?page=ipr
Parts of this schema are based on Subclause 6.5.7 of ISO/CD 19103 Geographic information - Conceptual schema language, on Subclause A.5.2.2.3 of ISO/CD 19118 Geographic information - Encoding, and on Subclause 4.7 of OpenGIS Recommendation Paper OGC 02-007r4 Units of Measure Use and Definition Recommendations.</documentation>
<!-- This schema uses the gml:MeasureType defined in basicTypes.xsd with the modified meaning:
<documentation>Value of a quantity, with its units. This element uses the XML Schema primitive data type "double" because it supports both decimal and scientific notation, and thus offers flexibility and precision. However, there is no requirement to store values using any particular format, and applications receiving elements of this type may choose to coerce the data to any other type as convenient. The XML attribute uom references the units or scale by which the amount should be multiplied. For a reference within the same XML document, the abbreviated XPointer prefix "#" symbol should be used, followed by a text abbreviation of the unit name. However, the "#" symbol may be optional, and still may be interpreted as a reference. </documentation> -->
<documentation>Value of a length (or distance) quantity, with its units. Uses the MeasureType with the restriction that the unit of measure referenced by uom must be suitable for a length, such as metres or feet.</documentation>
<documentation>Value of a scale factor (or ratio) that has no physical unit. Uses the MeasureType with the restriction that the unit of measure referenced by uom must be suitable for a scale factor, such as percent, permil, or parts-per-million.</documentation>
<documentation>Value of a time or temporal quantity, with its units. Uses the MeasureType with the restriction that the unit of measure referenced by uom must be suitable for a time value, such as seconds or weeks.</documentation>
<documentation>Value of a length (or distance) quantity in a grid, where the grid spacing does not have any associated physical units, or does not have a constant physical spacing. This grid length will often be used in a digital image grid, where the base units are likely to be pixel spacings. Uses the MeasureType with the restriction that the unit of measure referenced by uom must be suitable for length along the axes of a grid, such as pixel spacings or grid spacings.</documentation>
<documentation>Value of a spatial area quantity, with its units. Uses the MeasureType with the restriction that the unit of measure referenced by uom must be suitable for an area, such as square metres or square miles.</documentation>
<documentation>Value of a spatial volume quantity, with its units. Uses the MeasureType with the restriction that the unit of measure referenced by uom must be suitable for a volume, such as cubic metres or cubic feet.</documentation>
<documentation>Value of a speed, with its units. Uses the MeasureType with the restriction that the unit of measure referenced by uom must be suitable for a velocity, such as metres per second or miles per hour.</documentation>
<documentation>Value of an angle quantity recorded as a single number, with its units. Uses the MeasureType with the restriction that the unit of measure referenced by uom must be suitable for an angle, such as degrees or radians.</documentation>
<documentation>Integer number of degrees, plus the angle direction. This element can be used for geographic Latitude and Longitude. For Latitude, the XML attribute direction can take the values "N" or "S", meaning North or South of the equator. For Longitude, direction can take the values "E" or "W", meaning East or West of the prime meridian. This element can also be used for other angles. In that case, the direction can take the values "+" or "-" (of SignType), in the specified rotational direction from a specified reference direction.</documentation>
<documentation>How to encode reference system definitions. Builds on several other parts of GML 3 to encode the data needed to define reference systems.
Copyright (c) 2002-2005 OGC, All Rights Reserved. For conditions, see OGC Software Notice http://www.opengeospatial.org/about/?page=ipr
This schema encodes the Reference System (RS_) package of the extended UML Model for OGC Abstract Specification Topic 2: Spatial Referencing by Coordinates. That UML model is adapted from ISO 19111 - Spatial referencing by coordinates, as described in Annex C of Topic 2. The SC_CRS class is also encoded here, to eliminate the (circular) references from coordinateOperations.xsd to coordinateReferenceSystems.xsd. The RS_SpatialReferenceSystemUsingGeographicIdentifier class is not encoded, since it is not applicable to coordinate positions. The CI_Citation class is not directly encoded, since such information can be included as metaDataProperty elements which are optionally allowed. A modified version of the EX_Extent (DataType) class from ISO 19115 is currently encoded here, using GML 3 schema types. (A more extensive version of the EX_Extent package might be XML encoded in the future, probably in a separate extent.xsd schema.)
Caution: The CRS package in GML 3.1 and GML 3.1.1 is preliminary, and is expected to undergo some modifications that are not backward compatible during the development of GML 3.2 (ISO 19136). The GML 3.2 package will implement the model described in the revised version of ISO 19111.</documentation>
<documentation>Set of alterative identifications of this reference system. The first srsID, if any, is normally the primary identification code, and any others are aliases.</documentation>
</annotation>
</element>
<elementref="gml:remarks"minOccurs="0">
<annotation>
<documentation>Comments on or information about this reference system, including source information.</documentation>
<documentation>Abstract coordinate reference system, usually defined by a coordinate system and a datum. This abstract complexType shall not be used, extended, or restricted, in an Application Schema, to define a concrete subtype with a meaning equivalent to a concrete subtype specified in this document.</documentation>
<documentation>An identification of a CRS object. The first use of the IdentifierType for an object, if any, is normally the primary identification code, and any others are aliases.</documentation>
</annotation>
<sequence>
<elementref="gml:name">
<annotation>
<documentation>The code or name for this Identifier, often from a controlled list or pattern defined by a code space. The optional codeSpace attribute is normally included to identify or reference a code space within which one or more codes are defined. This code space is often defined by some authority organization, where one organization may define multiple code spaces. The range and format of each Code Space identifier is defined by that code space authority. Information about that code space authority can be included as metaDataProperty elements which are optionally allowed in all CRS objects.</documentation>
</annotation>
</element>
<elementref="gml:version"minOccurs="0"/>
<elementref="gml:remarks"minOccurs="0">
<annotation>
<documentation>Remarks about this code or alias.</documentation>
<documentation>Identifier of the version of the associated codeSpace or code, as specified by the codeSpace or code authority. This version is included only when the "code" or "codeSpace" uses versions. When appropriate, the version is identified by the effective date, coded using ISO 8601 date format.</documentation>
<documentation>Information about the spatial, vertical, and/or temporal extent of a reference system object. Constraints: At least one of the elements "description", "boundingBox", "boundingPolygon", "verticalExtent", and temporalExtent" must be included, but more that one can be included when appropriate. Furthermore, more than one "boundingBox", "boundingPolygon", "verticalExtent", and/or temporalExtent" element can be included, with more than one meaning the union of the individual domains.</documentation>
</annotation>
<sequence>
<elementref="gml:description"minOccurs="0">
<annotation>
<documentation>Description of spatial and/or temporal extent of this object.</documentation>
</annotation>
</element>
<choice>
<annotation>
<documentation>Geographic domain of this reference system object.</documentation>
<documentationxml:lang="en">The Temporal Reference Systems schema for GML 3.1 provides constructs for handling various styles of temporal reference system.
This schema reflects a partial implementation of the model described in ISO 19108:2002.
Copyright (c) 2002-2005 OGC, All Rights Reserved.
For conditions, see OGC Software Notice http://www.opengeospatial.org/about/?page=ipr</documentation>
<documentationxml:lang="en">A temporal coordinate system is based on a continuous interval scale defined in terms of a single time interval.</documentation>
<documentation>An Era may be composed of several member Eras. The "member" element implements the association to the Era at the next level down the hierarchy. "member" follows the standard GML property pattern whereby its (complex) value may be either described fully inline, or may be the target of a link carried on the member element and described fully elsewhere, either in the same document or from another service.</documentation>
<documentation>In a particular Time System, an Era may be a member of a group. The "group" element implements the back-pointer to the Era at the next level up in the hierarchy.
If the hierarchy is represented by describing the nested components fully in the their nested position inside "member" elements, then the parent can be easily inferred, so the group property is unnecessary.
However, if the hierarchy is represented by links carried on the "member" property elements, pointing to Eras described fully elsewhere, then it may be useful for a child (member) era to carry an explicit pointer back to its parent (group) Era.</documentation>
