[OSM-talk] Freemap in Mercator

[Christopher Schmidt]

On Wed, Jul 05, 2006 at 01:27:08AM +0100, Dean Earley wrote:
> Christopher Schmidt wrote:
> >http://london.freemap.in/july.mercator.html
> >
> >A bit slower, not fully optimized yet, but the biggest drain is the
> >satellite cache -- I'll prebuild that soon, and loading the vector data
> >on top of that is simple.
> >
> >The Permalinks are obviously not in degrees lat/lon, but that math
> >shouldn't be too hard to include in the OpenLayers.Control.Permalink so
> >that we can link out to the applet in the way it expects.. 
> >
> >I'll publish a tutorial on how to create cartographic styles tomorrow or
> >the next day, so that all you people telling me 'the colors are wrong!'
> >can give me lines of mapfile to fix it ;)
> >
> >Any non-speed, non-cartographic complaints?
> 
> The "measure distance" feature doesn't appear to work correctly (unless 
> the two lanes of a dual carriage way really ar 14 thousand Km apart...)

Doh! Of course they won't be, as that feature is dependant on the
projection. Hm. I'll have to do some thinking on fixing that generally
in OpenLayers, but I can fix it for the meantime. Although really, the
'measure distance' functionality was never completely supported... ;)

It's probably about 14000/40000 km apart, as the current assumption is
that the measure is in degrees... but I'm not sure exactly on the math
behind it, it uses one of the OpenLayers.Util.circleDistance functions
that I never really understood ;)

-- 
Christopher Schmidt
Web Developer