I assume you are referring to the OpenLayers based slippy map at openstreetmap.org? The Openlayers 2.8 ScaleLine class has the the problem that it does not handle that the map-scale is not constant accoss the map. The slippy map uses mercators projection, where the scale increases with 1/cos(lattiude). So the scaleline is correct at equator, but a over factor 2 off where I am at 62 north.
But it is trivial to make a mercator-specific variant of ScaleLine. I have made one here: http://www.egil-hjelmeland.no/kart/mercatorScaleLine.js. Anyone are free to use it. View it in action at my playground: http://www.egil-hjelmeland.no/kart/ . It is also very easy to make measurement functions in OpenLayers. And the good thing is that the OpenLayers Measure class is geodesic aware, it handles mercator out of the box. I think it would be good to include that on the OSM main map, as well. Cheers Egil H > > There used to be a distance indicator graphic in the bottom left of the map. > I believe it was removed because it was inaccurate due to the curvature > of the Earth. > > I can understand the point at low zoom levels, but at say, zoom 13, just > how inaccurate, percentage wise, is it? > > I found it quite useful as a guide. Obviously I didn't do any intricate > journey calculations based on it, but as a ball park figure, it came in use. > > Could it be reinstated for the higher level zooms, >11 maybe? > > Cheers > Dave F. > > _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
