[postgis-users] Buffer/Nautical Miles

Blake Crosby me at blakecrosby.com
Thu Sep 11 13:36:33 PDT 2008


I'm trying to create "circles" by using the buffer function around a point.

The radius values i'm working with are in nautical miles. The definition 
of a nautical mile is 1 minute of 1 degree.

Since this unit of measurement is based on a degree, and WSG84 is based 
on degrees of lat/long (and not meters like UTM) will the following be 
valid for a circle with a radius of 2 nautical miles around point 
(72.3,-45.3)?

st_buffer(st_geomfromtext('POINT(-45.3 72.3)', 4326), 0.0166667*2)

I'm trying to troubleshoot a problem I'm having and want to rule out any 
issues with my usage of buffer.

Blake



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