[OSM-dev] Units in the PostGIS database - what are they?
nick at hogweed.org
Sat Mar 17 22:51:24 GMT 2007
I'm getting unexpected results with the units used in the PostGIS database -
namely they don't seem to be metres. I would expect metres out of a Mercator
Using Nick Burch's Where Am I? script, the distance between the villages of
Fernhurst, West Sussex and Cheriton, Hampshire is 31km - they are on the same
latitude. From my knowledge of the area, 31km or about 20 miles seems about
However, the difference between the eastings is greater than 31000 metres.
Cheriton has an easting of approximately -130000. Fernhurst has an easting of
approximately -80000, giving a distance of 50km if the units were metres....
so clearly they are not.
Also, Fernhurst is less than 80km west of the Greenwich Meridian - more like
So... what units are the PostGIS coordinates in?
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