Switching to a different projection based on zoom level

Question

I have a map on my Geoserver, which I am displaying via wms and Openlayers. I am using a projection that is optimal for the whole area. However, when zooming in I would like to switch to a different projection which has proved to be best for a particular locality.

How can I achieve this? Any examples out there?

Answer 1

The methodology would be to detect a zoom change and apply a updated view with the new projection to the map.

First you have to detect the change of the resolution:

map.getView().on('change:resolution', changeProjection);

Secondly you look if you have reached the desired zoom level and then apply the projection:

var changeProjection = function() {
  var zoomLevel = map.getView().getZoom();

  // look if zoom level is reached
  if (zoomLevel > 15) {

    //define new view and apply to map
    map.setView(new ol.View({
      center: map.getView().getCenter(),
      zoom: zoomLevel,
      projection: newProjection /* typeof == ol.proj.ProjectionLike */
  });
}

Note: The code is untested and you have to set variable newProjection to make it work.