[OSM-dev] Default scale / meters per unit ?

Tom Hughes tom at compton.nu
Wed Sep 30 12:55:05 BST 2009


On 30/09/09 12:14, Jonas Donovan Hansen wrote:

> When importing openstreetmap with osm2pgsql and default settings
> (900913) – how many meters is a unit?

The units are meters, but meters on the projected map not great circle 
meters on the surface of the earth.

What osm2pgsql does when you import in that mode is to project the data 
onto a giant flat sheet - effectively it unrolls the globe and stretches 
it until it is flat. The resulting coordinates are in meters but meters 
on that imaginary projected surface.

Tom

-- 
Tom Hughes (tom at compton.nu)
http://www.compton.nu/




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