dynamically finding crs nodes from xml if matching with preferred crs. if not but has nodes then take first available node from xml. if none apply take our first preferred crs

Assets/_BuildingBlocks/OGCWebServices/Shared/BaseRequest.cs

@@ -105,6 +105,18 @@ protected string GetInnerTextForNode(XmlNode layerNode, string nodeName, bool se
             }
         }
 
+        protected XmlNodeList GetNodesByName(XmlNode layerNode, string nodeName)
+        {
+            var queryForNode = $"*[local-name()='{nodeName}']";
+            return layerNode.SelectNodes($".//{queryForNode}", namespaceManager);
+        }
+
+        protected XmlNodeList GetNodesByNameAndAttributes(XmlNode layerNode, string nodeName)
+        {
+            var queryForNode = $"//*[local-name()='{nodeName}' or @*='{nodeName}']";
+            return layerNode.SelectNodes(queryForNode, namespaceManager);
+        }
+
         protected XmlNode GetSingleNodeByName(XmlNode layerNode, string nodeName, bool searchInParents = false)
         {
             // Base query that will attempt to find the node; but we need more ...

Assets/_Functionalities/Wms/Scripts/WmsGetCapabilities.cs

@@ -4,6 +4,7 @@
 using System.Xml;
 using Netherlands3D.Coordinates;
 using Netherlands3D.OgcWebServices.Shared;
+using Netherlands3D.Twin.ExtensionMethods;
 using Netherlands3D.Twin.Utility;
 using UnityEngine;
 
@@ -13,6 +14,7 @@ public class WmsGetCapabilities : BaseRequest, IGetCapabilities
     {
         public Uri GetCapabilitiesUri => Url;
         public const string DefaultFallbackVersion = "1.3.0";
+        private CoordinateSystem[] preferredCRS = { CoordinateSystem.RD, CoordinateSystem.WGS84_LatLon, CoordinateSystem.CRS84 };
 
         public ServiceType ServiceType => ServiceType.Wms;
         protected override Dictionary<string, string> defaultNameSpaces => new()
@@ -24,6 +26,8 @@ public class WmsGetCapabilities : BaseRequest, IGetCapabilities
             { "schemaLocation", "http://www.opengis.net/wms" }
         };
 
+        private Dictionary<CoordinateSystem, string> supportedCrsDictionary = new Dictionary<CoordinateSystem, string>();
+
         public bool CapableOfBoundingBoxes => xmlDocument.SelectSingleNode("//*[local-name()='EX_GeographicBoundingBox' or local-name()='BoundingBox']", namespaceManager) != null;
 
         public bool HasBounds //todo: this is suboptimal because it uses the GetBounds function, maybe cache the bounds
@@ -184,13 +188,18 @@ public List<MapFilters> GetMaps(int width, int height, bool transparent)
                 // Extract styles for the layer
                 var styles = ExtractStyles(mapNode);
 
-                // CRS/SRS may be defined in the current MapNode, but can also inherit from a parent if it is not
-                // specified the flag at the end of this function will check the current node and its parents
-                var spatialReference = GetInnerTextForNode(mapNode, mapTemplate.spatialReferenceType, true);
-
-                // TODO: Really ugly fix to deal issues around EPSG:4326. So we fixate on CRS:84 now, hoping that will
-                // work in all situations
-                spatialReference = "CRS:84";
+                string spatialReference = null;
+                var spatialReferenceType = MapFilters.SpatialReferenceTypeFromVersion(new Version(mapTemplate.version));
+                XmlNodeList crsNodes = GetNodesByName(mapNode, spatialReferenceType);
+                if (crsNodes.Count == 0)
+                    crsNodes = GetNodesByNameAndAttributes(mapNode, spatialReferenceType);
+
+                HasSupportedCRS(crsNodes, out spatialReference);
+                if (string.IsNullOrEmpty(spatialReference))
+                {
+                    Debug.LogError("there is no CRS/SRS defined in the xml for this layer");
+                    continue;
+                }
 
                 var map = new MapFilters()
                 {
@@ -210,6 +219,44 @@ public List<MapFilters> GetMaps(int width, int height, bool transparent)
             return maps;
         }
 
+        private bool HasSupportedCRS(XmlNodeList crsNodes, out string crsToUse)
+        {
+            supportedCrsDictionary.Clear();
+
+            //parse all available crs nodes
+            foreach (XmlNode crsNode in crsNodes)
+            {
+                var crsText = crsNode.InnerText;
+                crsText = crsText == "CRS:84" ? "CRS84" : crsText;
+                var hasCRS = CoordinateSystems.FindCoordinateSystem(crsText, out var crs);
+                if (hasCRS)
+                {
+                    supportedCrsDictionary.Add(crs, crsNode.InnerText);
+                }
+            }
+
+            //try to get the preferred crs out of the list of available crses  
+            foreach (var crs in preferredCRS)
+            {
+                if (supportedCrsDictionary.ContainsKey(crs))
+                {
+                    crsToUse = supportedCrsDictionary[crs];
+                    return true;
+                }
+            }
+
+            // our preferred crses are not available, use the first supported one
+            if (supportedCrsDictionary.Count > 0)
+            {
+                crsToUse = supportedCrsDictionary.Values.First();
+                return true;
+            }
+
+            //none of the crsses available in the WMS are supported by us
+            crsToUse = null;
+            return false;
+        }
+
         private MapFilters CreateMapTemplate(int width, int height, bool transparent)
         {
             var version = GetVersion();