From 14625c86bf90ab817ed29141bf871d2b08adb51e Mon Sep 17 00:00:00 2001
From: "stuart.woodman" <stuart.woodman@csiro.au>
Date: Fri, 2 Aug 2024 11:37:26 +1000
Subject: [PATCH] Add Min/MaxScaleDenominators to a GetCapabilityRecord's
 LayerModels (if present).

---
 .../src/lib/model/data/layer.model.ts         |  2 +
 .../src/lib/service/wms/get-caps.service.ts   | 45 ++++++++++++++++++-
 2 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/projects/portal-core-ui/src/lib/model/data/layer.model.ts b/projects/portal-core-ui/src/lib/model/data/layer.model.ts
index 41cd701..cd042cd 100644
--- a/projects/portal-core-ui/src/lib/model/data/layer.model.ts
+++ b/projects/portal-core-ui/src/lib/model/data/layer.model.ts
@@ -40,4 +40,6 @@ export class LayerModel {
   kmlDoc: any; // Document object for custom KML layer
   serverType?: string;  // Type of server hosting the data
   initialLoad: boolean; // if first time loaded, zoom to bbox
+  minScaleDenominator?: number;  // MinScaleDenominator (from GetCapabilities)
+  maxScaleDenominator?: number;  // MaxScaleDenominator (from GetCapabilities)
 }
diff --git a/projects/portal-core-ui/src/lib/service/wms/get-caps.service.ts b/projects/portal-core-ui/src/lib/service/wms/get-caps.service.ts
index 0e943d0..f987cc1 100644
--- a/projects/portal-core-ui/src/lib/service/wms/get-caps.service.ts
+++ b/projects/portal-core-ui/src/lib/service/wms/get-caps.service.ts
@@ -258,6 +258,42 @@ export class GetCapsService {
     return SimpleXMLService.evaluateXPathString(doc, node, LEGEND_URL, nsResolver);
   }
 
+  /**
+   * Get a layer Node's MinScaleDenominator
+   *
+   * @param doc the root Document for the GetCapabilities response
+   * @param node the layer Node
+   * @param nsResolver namespace resolver function
+   * @returns the MinScaleDenomintor for the layer, or null if not present
+   */
+  private getMinScaleDenominator(doc: Document, node: Node, nsResolver: (prefix: string) => string): number {
+    let minScaleDenominator = null;
+    const METADATA_URL = './xsi:MinScaleDenominator';
+    const stringVal = SimpleXMLService.evaluateXPathString(doc, node, METADATA_URL, nsResolver);
+    if (stringVal && stringVal !== '') {
+      minScaleDenominator = parseFloat(stringVal);
+    }
+    return minScaleDenominator;
+  }
+
+  /**
+   * Get a layer Node's MaxScaleDenominator
+   *
+   * @param doc the root Document for the GetCapabilities response
+   * @param node the layer Node
+   * @param nsResolver namespace resolver function
+   * @returns the MaxScaleDenomintor for the layer, or null if not present
+   */
+  private getMaxScaleDenominator(doc: Document, node: Node, nsResolver: (prefix: string) => string): number {
+    let maxScaleDenominator = null;
+    const METADATA_URL = './xsi:MaxScaleDenominator';
+    const stringVal = SimpleXMLService.evaluateXPathString(doc, node, METADATA_URL, nsResolver);
+    if (stringVal && stringVal !== '') {
+      maxScaleDenominator = parseFloat(stringVal);
+    }
+    return maxScaleDenominator;
+  }
+
   /**
    * Test if the layer should use a post request.
    * NOTE: In the future if we parse styles this should also factor in the request length
@@ -318,6 +354,10 @@ export class GetCapsService {
       const metadataUrl = this.getMetadataUrl(rootNode, layerNode, this.nsResolver);
       const legendUrl = this.getLegendUrl(rootNode, layerNode, this.nsResolver);
 
+      // Only some layers will have Min/MaxScaleDenominators, these can affect if a layer will display at some zoom levels
+      const minScaleDenominator = this.getMinScaleDenominator(rootNode, layerNode, this.nsResolver);
+      const maxScaleDenominator = this.getMaxScaleDenominator(rootNode, layerNode, this.nsResolver);
+
       // One cswRecord object per layer
       retVal.data.cswRecords.push({
         name: cswRecElems['name'],
@@ -356,7 +396,6 @@ export class GetCapsService {
           mapFormats: mapFormats,
           applicationProfile: applicationProfile,
           accessConstraints:accessConstraints
-
         }];
       }
 
@@ -368,7 +407,9 @@ export class GetCapsService {
           metadataUrl: metadataUrl,
           legendUrl: legendUrl,
           timeExtent: timeExtent,
-          bbox: geoElems
+          bbox: geoElems,
+          minScaleDenominator: minScaleDenominator,
+          maxScaleDenominator: maxScaleDenominator
       });
     }
     return retVal;