Layer URL parameter

The layer URL parameter on the OpenStreetMap homepage is one of several parameters forming a 'permalink' URL. It takes a special code representing your layer selection, so that others following your permalink will see the map browsing interface initialised with the same layer selection.

The parameter is optional and if you leave it out, we will default to showing the best map layer we have to offer (currently "mapnik").

Future changes

If you do link to a layer code to select a different layer, note that we may not be able to guarantee that this code will remain the same forever. Your permalink URLs are unlikely to ever break completely (we'll always try to show the map in the right place) but a change in layer definitions may mean your link ends up pointing at a different layer selection. That said, we will endeavour to keep things the same to avoid changing the behaviour of incoming links.

Layer code structure

The layer code currently works as follows:

M = Mapnik

O = Osmarender

C = Cyclemap

T = Transport Map

Q = MapQuest Open

N = NoName

Historical notes

The parameters where formatted in OpenLayers URL parameters style, but was simplified in 2010 making this scheme specific for OSM.