h the &#x27;EPSG:21781&#x27; code,
// OpenLayers will pick up parameters like units and transform functions from
// Proj4js.
//
// Note that we are setting the projection&#x27;s extent here, which is used to
// determine the view resolution for zoom level 0. Recommended values for a
// projection&#x27;s validity extent can be found at https://epsg.io/.
//
// If you use Proj4js only to transform coordinates, you don&#x27;t even need to
// create an ol.proj.Projection instance. ol.proj.get() will take care of