Use fromProjectionCode instead of fromEPSGCode (#21)

* Use fromEPSGCode or fromProjectionCode depending on ol version

Author: m-mohr

src/ol/source/GeoTIFF.js

@@ -12,7 +12,6 @@ import {error as logError} from 'ol/console.js';
 import {applyTransform, getCenter, getIntersection} from 'ol/extent.js';
 import {clamp} from 'ol/math.js';
 import {fromCode as unitsFromCode} from 'ol/proj/Units.js';
-import {fromEPSGCode} from 'ol/proj/proj4.js';
 import {
   Projection,
   createTransformFromCoordinateTransform,
@@ -28,6 +27,7 @@ import {
   makeInverse,
   multiply as multiplyTransform,
 } from 'ol/transform.js';
+import {loadProjection} from '../util.js';
 
 /**
  * Determine if an image type is a mask.
@@ -196,11 +196,7 @@ async function getProjectionFromKeys(
     const code = 'EPSG:' + value;
     let projection = getCachedProjection(code);
     if (!projection && loadMissingProjection) {
-      try {
-        projection = await fromEPSGCode(value);
-      } catch {
-        // pass
-      }
+      projection = await loadProjection(code);
     }
     if (!projection) {
       const units = unitsFromCode(geoKeys[unitKey]);

src/ol/util.js

@@ -3,10 +3,7 @@
  */
 
 import VectorLayer from 'ol/layer/Vector.js';
-import {
-  fromEPSGCode,
-  isRegistered as isProj4Registered,
-} from 'ol/proj/proj4.js';
+import {isRegistered as isProj4Registered} from 'ol/proj/proj4.js';
 import Circle from 'ol/style/Circle.js';
 import Fill from 'ol/style/Fill.js';
 import Stroke from 'ol/style/Stroke.js';
@@ -23,6 +20,12 @@ import {STAC} from 'stac-js';
 /**
  * @typedef {import('ol/Feature.js').default} Feature
  */
+/**
+ * @typedef {import('ol/proj.js').Projection} Projection
+ */
+/**
+ * @typedef {import('ol/proj.js').ProjectionLike} ProjectionLike
+ */
 
 /**
  * The pattern for the supported versions of the label extension.
@@ -217,29 +220,43 @@ export function getGeoTiffSourceInfoFromAsset(asset, selectedBands) {
   return sourceInfo;
 }
 
+/**
+ * Load the projection for the given projection code from the internet.
+ *
+ * @param {string} code Projection code, e.g. 'EPSG:1234'
+ * @return {Promise<Projection|null>} The loaded projection
+ */
+export async function loadProjection(code) {
+  try {
+    // @ts-ignore - Support both old and new OpenLayers versions
+    const {fromProjectionCode, fromEPSGCode} = await import('ol/proj/proj4.js');
+    if (typeof fromProjectionCode === 'function') {
+      // Supported since ol v10.8.0
+      return await fromProjectionCode(code);
+    }
+    // Supported until ol v11.0.0
+    return await fromEPSGCode(code);
+  } catch (_) {
+    return null;
+  }
+}
+
 /**
  * Gets the projection from the asset or link.
  * @param {import('stac-js').STACReference} reference The asset or link to read the information from.
- * @param {import('ol/proj.js').ProjectionLike} defaultProjection A default projection to use.
- * @return {Promise<import('ol/proj.js').ProjectionLike>} The projection, if any.
+ * @param {ProjectionLike} defaultProjection A default projection to use.
+ * @return {Promise<ProjectionLike>} The projection, if any.
  */
 export async function getProjection(reference, defaultProjection = undefined) {
-  let projection = defaultProjection;
+  let projection;
   if (isProj4Registered()) {
     // TODO: It would be great to handle WKT2 and PROJJSON, but is not supported yet by proj4js.
     const code = reference.getMetadata('proj:code');
     if (code) {
-      try {
-        if (code.startsWith('EPSG:')) {
-          const id = parseInt(code.replace('EPSG:', ''), 10);
-          projection = await fromEPSGCode(id);
-        }
-      } catch (_) {
-        // pass
-      }
+      projection = await loadProjection(code);
     }
   }
-  return projection;
+  return projection || defaultProjection;
 }
 
 /**