Hello Wayne! There is no "easy" way for doing coordinate transformations since there is a lot you have to take into account. I am not sure what programming language you want to use, but if it is Javascript you might dive into proj4js http://proj4js.org/ and see if it offers libraries you can use.
Good luck, Milo van der Linden Wayne Walker wrote: > I'm not using slippy map. For the project I'm doing I need static > images. I just can't sort out the math to find the veritcal position in > the tile map. I've tried mercator projection but I'm missing something. > > I've tried to follow the logic in the javascript of the slippy map, but > without comments and with short var/function names I get lost. > > Does anyone have a simple formula such that: > > y = ....(lat)? > > I've tried things like: > > k = 4.0 > y = log(tan(y*Math::PI/180.0) + 1/cos(y*Math::PI/180.0))/k > > Which is the mercator projection formula (substituting 1/cos for sec) > from wikipedia. > > Also tried a Miller cylindrical projection as that seems much more like > what the main tile looks like. > > miller=2.30341254337639 > > y = 1.25 * log(tan(Math::PI/4 + 0.8 * (y*Math::PI/180.0)/2))/miller > > > > No joy there either. > > Any ideas? > > _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/dev
