OpenLayers data moves when panning map

Question

I have an OpenLayers map.

On to this I have loaded a GeoJSON file.

When I pan the map the GeoJSON data moves relative to the basemap.

Surely this isn't right! Can anyone shed some light no why this is happening?

Answer 1

This happened to me once and the layer was not on the same projection as the basemap.

But without example code, this is like a stab in the dark.

Answer 2

The most likely cause of this is not setting a baselayer's sphericalMercator property to true - by default this is false, so it needs to be set explicitly.

var myBaseLayer = new OpenLayers.Layer.Google("Google",
              {'sphericalMercator': true
              });

APIProperty: sphericalMecator Whether the tile extents should be set to the defaults for spherical mercator. Useful for things like OpenStreetMap. Default is false, except for the OSM subclass.