improve createLayer from WMTS Capabilities

lib/OpenLayers/Format/WMTSCapabilities.js

@@ -68,7 +68,12 @@ OpenLayers.Format.WMTSCapabilities = OpenLayers.Class(OpenLayers.Format.XML.Vers
      *
      * Required config properties:
      * layer - {String} The layer identifier.
-     * matrixSet - {String} The matrix set identifier.
+     *
+     * Optional config properties:
+     * matrixSet - {String} The matrix set identifier, required if there is 
+     *      more than one matrix set in the layer capabilities.
+     * style - {String} The name of the style
+     * param - {Object} The dimensions values eg: {"Year": "2012"}
      *
      * Returns:
      * {<OpenLayers.Layer.WMTS>} A properly configured WMTS layer.  Throws an
@@ -79,18 +84,11 @@ OpenLayers.Format.WMTSCapabilities = OpenLayers.Class(OpenLayers.Format.XML.Vers
         var layer;
 
         // confirm required properties are supplied in config
-        var required = {
+        if (!('layer' in config)) {
-            layer: true,
+            throw new Error("Missing property 'layer' in configuration.");
-            matrixSet: true
-        };
-        for (var prop in required) {
-            if (!(prop in config)) {
-                throw new Error("Missing property '" + prop + "' in layer configuration.");
-            }
         }
 
         var contents = capabilities.contents;
-        var matrixSet = contents.tileMatrixSets[config.matrixSet];
 
         // find the layer definition with the given identifier
         var layers = contents.layers;
@@ -101,30 +99,95 @@ OpenLayers.Format.WMTSCapabilities = OpenLayers.Class(OpenLayers.Format.XML.Vers
                 break;
             }
         }
+        if (!layerDef) {
+            throw new Error("Layer not found");
+        }
 
-        if (layerDef && matrixSet) {
+        // find the matrixSet definition
-            // get the default style for the layer
+        var matrixSet;
-            var style;
+        if (config.matrixSet) {
-            for (var i=0, ii=layerDef.styles.length; i<ii; ++i) {
+            matrixSet = contents.tileMatrixSets[config.matrixSet];
-                style = layerDef.styles[i];
+        } else if (layerDef.tileMatrixSetLinks.length == 1) {
-                if (style.isDefault) {
+            matrixSet = contents.tileMatrixSets[
-                    break;
+                layerDef.tileMatrixSetLinks[0].tileMatrixSet];
+        }
+        if (!matrixSet) {
+            throw new Error("matrixSet not found");
+        }
+
+        // get the default style for the layer
+        var style;
+        for (var i=0, ii=layerDef.styles.length; i<ii; ++i) {
+            style = layerDef.styles[i];
+            if (style.isDefault) {
+                break;
+            }
+        }
+
+        var requestEncoding = config.requestEncoding;
+        if (!requestEncoding) {
+            requestEncoding = "KVP";
+            if (capabilities.operationsMetadata.GetTile.dcp.http) {
+                var http = capabilities.operationsMetadata.GetTile.dcp.http;
+                // Get first get method
+                if (http.get[0].constraints) {
+                    var constraints = http.get[0].constraints;
+                    if (!constraints.GetEncoding.allowedValues.KVP &&
+                            constraints.GetEncoding.allowedValues.REST) {
+                        requestEncoding = "REST";
+                    }
                 }
             }
-            
-            layer = new OpenLayers.Layer.WMTS(
-                OpenLayers.Util.applyDefaults(config, {
-                    url: config.requestEncoding === "REST" && layerDef.resourceUrl ?
-                        layerDef.resourceUrl.tile.template :
-                        capabilities.operationsMetadata.GetTile.dcp.http.get[0].url,
-                    name: layerDef.title,
-                    style: style.identifier,
-                    matrixIds: matrixSet.matrixIds,
-                    tileFullExtent: matrixSet.bounds
-                })
-            );
         }
-        return layer;
+
+        var dimensions = [];
+        var params = config.params || {};
+        // to don't overwrite the changes in the applyDefaults
+        delete config.params;
+        for (var id = 0, ld = layerDef.dimensions.length ; id < ld ; id++) {
+            var dimension = layerDef.dimensions[id];
+            dimensions.push(dimension.identifier);
+            if (!params.hasOwnProperty(dimension.identifier)) {
+                params[dimension.identifier] = dimension['default'];
+            }
+        }
+
+        var projection = config.projection || matrixSet.supportedCRS.replace(
+                /urn:ogc:def:crs:(\w+):.+:(\w+)$/, "$1:$2");
+        var units = config.units ||
+                projection === "EPSG:4326" ? "degrees" : "m"
+
+        var resolutions = [];
+        if (config.isBaseLayer !== false) {
+            for (mid in matrixSet.matrixIds) {
+                if (matrixSet.matrixIds.hasOwnProperty(mid)) {
+                    resolutions.push(
+                        matrixSet.matrixIds[mid].scaleDenominator * 0.28E-3
+                            / OpenLayers.METERS_PER_INCH
+                            / OpenLayers.INCHES_PER_UNIT[units]);
+                }
+            }
+        }
+
+        return new OpenLayers.Layer.WMTS(
+            OpenLayers.Util.applyDefaults(config, {
+                url: requestEncoding === "REST" && layerDef.resourceUrl ?
+                    layerDef.resourceUrl.tile.template :
+                    capabilities.operationsMetadata.GetTile.dcp.http.get[0].url,
+                requestEncoding: requestEncoding,
+                name: layerDef.title,
+                style: style.identifier,
+                matrixIds: matrixSet.matrixIds,
+                matrixSet: matrixSet.identifier,
+                projection: projection,
+                units: units,
+                resolutions: config.isBaseLayer === false ? undefined :
+                    resolutions,
+                tileFullExtent: matrixSet.bounds,
+                dimensions: dimensions,
+                params: params
+            })
+        );
     },
 
     CLASS_NAME: "OpenLayers.Format.WMTSCapabilities"

lib/OpenLayers/Layer/WMTS.js

@@ -106,6 +106,7 @@ OpenLayers.Layer.WMTS = OpenLayers.Class(OpenLayers.Layer.Grid, {
      * 
      * Matrix properties:
      * identifier - {String} The matrix identifier (required).
+     * scaleDenominator - {Number} The matrix scale denominator.
      * topLeftCorner - {<OpenLayers.LonLat>} The top left corner of the 
      *     matrix.  Must be provided if different than the layer <tileOrigin>.
      * tileWidth - {Number} The tile width for the matrix.  Must be provided