On 16 March 2012 15:47, Puneet Kishor <punk.k...@gmail.com> wrote:
> I am trying to create a simple 1 deg x 1 deg grid and transform it to
> spherical mercator
>
> SELECT ST_Transform(ST_MakeEnvelope(minx, miny, maxx, maxy, 4326),
> 900913) the_geom
> FROM (
> SELECT lng minx, lat miny, (lng + 1) maxx, (lat + 1) maxy
> FROM (
> SELECT Generate_series(-180, 180, 1) lng,
> Generate_series(-90, 90, 1) lat
> ) series
> WHERE (lng + 1) < 181 AND (lat + 1) < 91
> ) lat_lng
>
>
> I get
>
> ERROR: transform: couldn't project point (-180 -90 0): tolerance
> condition error (-20)
>
>
>
> What am I doing wrong?
Transform has difficulties at the poles, since the limits of math are stretched.
If you aren't gridding polar bears and/or penguins, then you should
use only latitudes from 79S to 79N. Try this:
SELECT ST_Transform(ST_MakeEnvelope(minx, miny, maxx, maxy, 4326),
900913) the_geom
FROM (
SELECT lng minx, lat miny, (lng + 1) maxx, (lat + 1) maxy
FROM (
SELECT Generate_series(-180, 179, 1) lng, Generate_series(-89,
88, 1) lat
) series
ORDER BY lng, lat
) lat_lng;
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