Human readable area

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

@@ -298,8 +298,7 @@ const regionChooser = (function(){
 		if (utils.is_polygon(geom)){ // It could be a MultiPolygon, for example.
 			var coordinates = geom.getLinearRing(0).getCoordinates();
 			var area = Math.abs(wgs84Sphere.geodesicArea(coordinates));
-			//NOTE: Could show m², ha or km² depending on magnitude
-			dataPanel.append("<h3 class='clean'>Area : " + (area / 10000).toFixed(1) + " ha\n");
+			dataPanel.append("<h3 class='clean'>Area : " + utils.human_readable_area(area) + "\n");
 		}
 		dataPanel.append('<div style="visibility:hidden" id="download_region">' +
 			'<button type="button" onclick="regionChooser.downloadFromSelectedCityGMLs()" id="download_region_button" disabled>Download Region</button><br/>\n' +

src/main/resources/eu/simstadt/regionchooser/website/script/utils.js

@@ -66,3 +66,13 @@ utils.polygon_style = function (color, alpha) {
 		}),
 	});
 }
+
+utils.human_readable_area = function (area) {
+	if (area > 1_000_000) {
+		return (area / 1_000_000).toFixed(1) + " km²";
+	}
+	if (area > 10_000) {
+		return (area / 10_000).toFixed(1) + " ha";
+	}
+	return area.toFixed(1) + " m²";
+}