Report WMS scale denominators (scale hints)

fixtures/wms/capabilities-brgm-1-1-1.xml

@@ -238,7 +238,7 @@
  <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://mapsref.brgm.fr/legendes/geoservices/Geologie1000_legende_other.jpg"/>
  </LegendURL>
  </Style>
- <ScaleHint min="74.8354272644456" max="3741.77136322228" />
+ <ScaleHint min="79.19595949289331" max="3959.7979746446654" />
  </Layer>
  <Layer queryable="true" opaque="true" cascaded="0">
  <Name>SCAN_F_GEOL250</Name>
@@ -273,7 +273,7 @@
  <Format>text/xml</Format>
  <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://www.geocatalogue.fr/api-public/servicesRest?Service=CSW&amp;Request=GetRecordById&amp;Version=2.0.2&amp;id=BR_CAR_ACA&amp;outputSchema=http://www.isotc211.org/2005/gmd&amp;elementSetName=full"/>
  </MetadataURL>
- <ScaleHint min="29.9341709057782" max="187.088568161114" />
+ <ScaleHint min="31.678383797157327" max="197.9898987322333" />
  </Layer>
  <Layer queryable="1" opaque="1" cascaded="0">
  <Name>SCAN_D_GEOL50</Name>
@@ -308,7 +308,11 @@
  <Format>text/xml</Format>
  <OnlineResource xmlns:xlink="http://www.w3.org/1999/xlink" xlink:type="simple" xlink:href="http://www.geocatalogue.fr/api-public/servicesRest?Service=CSW&amp;Request=GetRecordById&amp;Version=2.0.2&amp;id=72cc8d40-1bb6-41a3-8376-9734f23336ff&amp;outputSchema=http://www.isotc211.org/2005/gmd&amp;elementSetName=full"/>
  </MetadataURL>
- <ScaleHint min="3.36759422690005" max="93.9184612168792" />
+ <ScaleHint min="3.563818177180199" max="99.3909291635811" />
+ <Layer>
+ <Name>INHERIT_SCALE</Name>
+ <Title>Inherited scale denominators</Title>
+ </Layer>
  </Layer>
  <Layer queryable="0" opaque="0" cascaded="0">
  <Name>INHERIT_BBOX</Name>

fixtures/wms/capabilities-brgm-1-3-0.xml

@@ -329,6 +329,10 @@
  </MetadataURL>
  <MinScaleDenominator>9000</MinScaleDenominator>
  <MaxScaleDenominator>251000</MaxScaleDenominator>
+ <Layer>
+ <Name>INHERIT_SCALE</Name>
+ <Title>Inherited scale denominators</Title>
+ </Layer>
  </Layer>
  <Layer queryable="0" opaque="0" cascaded="0">
  <Name>INHERIT_BBOX</Name>

src/wms/capabilities.spec.ts

@@ -8,6 +8,7 @@ import capabilities130 from '../../fixtures/wms/capabilities-brgm-1-3-0.xml';
 // @ts-expect-error ts-migrate(7016)
 import capabilities111 from '../../fixtures/wms/capabilities-brgm-1-1-1.xml';
 import { parseXmlString } from '../shared/xml-utils.js';
+import type { WmsLayerFull } from './model.js';
 
 describe('WMS capabilities', () => {
  describe('readVersionFromCapabilities', () => {
@@ -132,6 +133,8 @@ describe('WMS capabilities', () => {
  'EPSG:4326': ['-5.86764', '41.1701', '11.0789', '51.1419'],
  },
  keywords: ['Geologie', 'INSPIRE:Geology', 'Geology'],
+ maxScaleDenominator: 1e7,
+ minScaleDenominator: 200000,
  name: 'SCAN_F_GEOL1M',
  queryable: false,
  opaque: false,
@@ -185,6 +188,8 @@ describe('WMS capabilities', () => {
  'EPSG:4326': ['-6.20495', '41.9671', '12.2874', '51.2917'],
  },
  keywords: ['Geologie', 'INSPIRE:Geology', 'Geology'],
+ maxScaleDenominator: 500000,
+ minScaleDenominator: 80000,
  name: 'SCAN_F_GEOL250',
  queryable: true,
  opaque: true,
@@ -225,11 +230,56 @@ describe('WMS capabilities', () => {
  'EPSG:4326': ['-12.2064', '40.681', '11.894', '52.1672'],
  },
  keywords: ['Geologie', 'INSPIRE:Geology', 'Geology'],
+ maxScaleDenominator: 251000,
+ minScaleDenominator: 9000,
  name: 'SCAN_D_GEOL50',
  queryable: true,
  opaque: true,
  styles,
  title: 'Carte géologique image de la France au 1/50 000e',
+ children: [
+ {
+ abstract: '',
+ attribution,
+ availableCrs: [
+ 'EPSG:4326',
+ 'EPSG:3857',
+ 'CRS:84',
+ 'EPSG:32620',
+ 'EPSG:32621',
+ ],
+ boundingBoxes: {
+ 'CRS:84': ['-12.2064', '40.681', '11.894', '52.1672'],
+ 'EPSG:32620': [
+ '3.88148e+06',
+ '6.13796e+06',
+ '6.31307e+06',
+ '8.70752e+06',
+ ],
+ 'EPSG:32621': [
+ '3.52434e+06',
+ '5.74736e+06',
+ '5.97375e+06',
+ '8.23867e+06',
+ ],
+ 'EPSG:3857': [
+ '-1.35881e+06',
+ '4.96541e+06',
+ '1.32403e+06',
+ '6.83041e+06',
+ ],
+ 'EPSG:4326': ['-12.2064', '40.681', '11.894', '52.1672'],
+ },
+ keywords: [],
+ maxScaleDenominator: 251000,
+ minScaleDenominator: 9000,
+ name: 'INHERIT_SCALE',
+ queryable: false,
+ opaque: false,
+ styles,
+ title: 'Inherited scale denominators',
+ },
+ ],
  },
  {
  abstract: '',
@@ -275,7 +325,9 @@ describe('WMS capabilities', () => {
  });
  it('reads the layers (1.1.1)', () => {
  const doc = parseXmlString(capabilities111);
- expect(readLayersFromCapabilities(doc)).toEqual(expectedLayers);
+ expect(
+ readLayersFromCapabilities(doc).map(fixupScaleDenominators)
+ ).toEqual(expectedLayers);
  });
  });
 
@@ -319,3 +371,18 @@ describe('WMS capabilities', () => {
  });
  });
 });
+
+/**
+ * Round scale denominators to avoid problems with floating point precision
+ * @param layer
+ */
+function fixupScaleDenominators(layer: WmsLayerFull): WmsLayerFull {
+ if (layer.minScaleDenominator !== undefined) {
+ layer.minScaleDenominator = Math.round(layer.minScaleDenominator);
+ }
+ if (layer.maxScaleDenominator !== undefined) {
+ layer.maxScaleDenominator = Math.round(layer.maxScaleDenominator);
+ }
+ layer.children?.forEach(fixupScaleDenominators);
+ return layer;
+}

src/wms/capabilities.ts

@@ -94,7 +94,9 @@ function parseLayer(
  inheritedSrs: CrsCode[] = [],
  inheritedStyles: LayerStyle[] = [],
  inheritedAttribution: WmsLayerAttribution = null,
- inheritedBoundingBoxes: Record<CrsCode, BoundingBox> = null
+ inheritedBoundingBoxes: Record<CrsCode, BoundingBox> = null,
+ inheritedMaxScaleDenom: number = null,
+ inheritedMinScaleDenom: number = null
 ): WmsLayerFull {
  const srsTag = version === '1.3.0' ? 'CRS' : 'SRS';
  const srsList = findChildrenElement(layerEl, srsTag).map(getElementText);
@@ -124,6 +126,30 @@ function parseLayer(
  getElementAttribute(bboxEl, name)
  );
  }
+ function parseScaleHintValue(textValue, defaultValue) {
+ if (textValue === '') {
+ return defaultValue;
+ }
+ // convert resolution to scale denominator using the common pixel size of
+ // 0.28×0.28 mm as defined in WMS 1.3.0 specification section 7.2.4.6.9
+ return Math.sqrt(0.5 * parseFloat(textValue) ** 2) / 0.00028;
+ }
+ function parseScaleHint() {
+ const scaleHint = findChildElement(layerEl, 'ScaleHint');
+ if (!scaleHint) {
+ return [inheritedMinScaleDenom, inheritedMaxScaleDenom];
+ }
+ const min = getElementAttribute(scaleHint, 'min');
+ const max = getElementAttribute(scaleHint, 'max');
+ return [
+ parseScaleHintValue(min, inheritedMinScaleDenom),
+ parseScaleHintValue(max, inheritedMaxScaleDenom),
+ ];
+ }
+ function parseScaleDenominator(name, inheritedValue) {
+ const textValue = getElementText(findChildElement(layerEl, name));
+ return textValue === '' ? inheritedValue : parseFloat(textValue);
+ }
  const attributionEl = findChildElement(layerEl, 'Attribution');
  const attribution =
  attributionEl !== null
@@ -169,8 +195,31 @@ function parseLayer(
  .map(getElementText)
  .filter((v, i, arr) => arr.indexOf(v) === i);
 
+ let minScaleDenominator, maxScaleDenominator;
+ if (version === '1.3.0') {
+ minScaleDenominator = parseScaleDenominator(
+ 'MinScaleDenominator',
+ inheritedMinScaleDenom
+ );
+ maxScaleDenominator = parseScaleDenominator(
+ 'MaxScaleDenominator',
+ inheritedMaxScaleDenom
+ );
+ } else {
+ [minScaleDenominator, maxScaleDenominator] = parseScaleHint();
+ }
+
  const children = findChildrenElement(layerEl, 'Layer').map((layer) =>
- parseLayer(layer, version, availableCrs, styles, attribution, boundingBoxes)
+ parseLayer(
+ layer,
+ version,
+ availableCrs,
+ styles,
+ attribution,
+ boundingBoxes,
+ maxScaleDenominator,
+ minScaleDenominator
+ )
  );
  return {
  name: getElementText(findChildElement(layerEl, 'Name')),
@@ -183,6 +232,8 @@ function parseLayer(
  keywords,
  queryable,
  opaque,
+ ...(minScaleDenominator !== null ? { minScaleDenominator } : {}),
+ ...(maxScaleDenominator !== null ? { maxScaleDenominator } : {}),
  ...(children.length && { children }),
  };
 }

src/wms/endpoint.spec.ts

@@ -89,6 +89,13 @@ describe('WmsEndpoint', () => {
  "BD Scan-Géol-50 est la base de données géoréférencées des cartes géologiques 'papier' à 1/50 000",
  name: 'SCAN_D_GEOL50',
  title: 'Carte géologique image de la France au 1/50 000e',
+ children: [
+ {
+ abstract: '',
+ name: 'INHERIT_SCALE',
+ title: 'Inherited scale denominators',
+ },
+ ],
  },
  {
  abstract: '',

src/wms/model.ts

@@ -34,6 +34,8 @@ export type WmsLayerFull = {
  boundingBoxes: Record<CrsCode, BoundingBox>;
  queryable: boolean;
  opaque: boolean;
+ maxScaleDenominator?: number;
+ minScaleDenominator?: number;
  attribution?: WmsLayerAttribution;
  keywords?: string[];
  /**