[postgis-users] Buffer/Nautical Miles

[Bruce Rindahl]

A nautical mile is 1 minute measured along a great circle on a sphere 
(such as the equator or a longitude line).  Thus your query will not 
work- it will be too short in the x direction.  If you are using UTM a 
nautical mile is about 1852 meters.

Bruce

Blake Crosby wrote:
> 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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