RegionChooser: Documentation.

src/eu/simstadt/regionchooser/website/script/simstadt_openlayers.js

@@ -304,7 +304,7 @@ var regionChooser = (function(){
 		try {
 			draw.finishDrawing();
 		} finally {
-			dataPanel.empty();
+			displayHelp();
 			$("html").removeClass("wait");
 			draw.setActive(true);
 			featureOverlay.getFeatures().clear();
@@ -362,10 +362,20 @@ var regionChooser = (function(){
 		}
 	}
 	
+	function displayHelp(){
+		dataPanel.empty();
+		dataPanel.append("Welcome to Region Chooser!<br><br>\n");
+		dataPanel.append("You can draw a polygon on the map by clicking.<br>\n");
+		dataPanel.append("You can add a new point to an existing edge by clicking and dragging.<br>\n");
+		dataPanel.append("You can remove a point with SHIFT + clicking.<br>\n");
+		dataPanel.append("You can cancel drawing with ESC or DEL.<br><br>\n");
+		dataPanel.append("After drawing a polygon which intersects with a GML file, you can download the corresponding part by clicking on the filename.<br>\n");
+	}
+
 	// Executed by JavaFX when whole page is loaded.
 	publicScope.ready = function() {
 		updateGMLPolygons();
-		dataPanel.empty();
+		displayHelp();
 		$("html").removeClass("wait");
 		console.log("READY!");
 	}