Just a very quick question:
Is there a way of gettting a scale bar to display on the map? (If that is not the right name for it, what I mean is a horizontal line which shows how long 1km or whatever is on the map)
It would be useful for me to work out what radius of tiles I need to download to OSMtracker, but I think it is a pretty fundamental part of a map anyway.
Try http://www.openstreetbrowser.org … there is a scale … but does it cover the whole planet?
Problem is that we use Mercator, so the horizontal scale varies as you move north and south. But there’s no reason there can’t be different horizontal and vertical scales displayed.
If you’re using your own OpenLayers map, you add a scale line with the OpenLayers.Control.ScaleLine control. See http://dev.openlayers.org/releases/OpenLayers-2.9.1/doc/apidocs/files/OpenLayers/Control/ScaleLine-js.html
I see it now has the option to set “geodesic: true”, which means the scale should be (mostly) correct at all latitudes.