[OSM-dev] Algorithm for converting lat/lon into Mercator as used in OSM PostGIS?

Nick Whitelegg nick at hogweed.org
Sun Mar 11 13:33:08 GMT 2007


On Sunday 11 Mar 2007 13:13, Kristian Thy wrote:
> On Sun, Mar 11, Nick Whitelegg wrote:
> > What would be really good, incidentally, would be a resource on the web
> > which explains all the subtleties with projections and ellipsoids (which
> > I probably only half-understand TBH), with appropriate conversion
> > equations, so that people who haven't done formal GIS training could read
> > and understand the theory and then easily implement the code. Maybe such
> > a resource exists though I haven't found it yet... Maybe it should go on
> > the OSM wiki?
>
> Maybe it's just me being daft, but is there any real reason you want to
> do this massive duplication of effort? Can't you just link to libproj?

Not if you want to implement it in javascript :-) (see earlier reference to 
wishing to avoid unneccessary computations server side) 
Besides, I'd like to understand what all these parameters actually *mean*...

Nick




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