[postgis-users] I can't make sense of this.

Paul Ramsey pramsey at opengeo.org
Thu May 20 09:57:39 PDT 2010


3857 is a Mercator projection. Your coordinates are geographics. If
you mis-declare your SRS (as, in your case, declaring that geographics
are mercators) then transform will spit out funny numbers on the basis
of that initial mistake.

P

On Thu, May 20, 2010 at 9:38 AM, Ronald Phillips
<rphillips at summitengineer.net> wrote:
> SELECT
>
>             ST_AsText(
>
>                         ST_GeomFromText('POINT(-81.064544 40.28787)', 3857)
>
>                         )
>
> AS goog,
>
>             ST_AsText(
>
>                         ST_Transform(
>
>                                     ST_GeomFromText('POINT(-81.064544
> 40.28787)', 3857)
>
>                         , 4326)
>
>             )
>
> AS gcs
>
>
>
> 3857 is “Google’s” SRID, and 4326 is a fairly standard GPS SRID. I’m getting
> this:
>
>
>
> Goog: "POINT(-81.064544 40.28787)";
>
> Gcs: "POINT(-0.000728215188753794 0.000361912093851508)"
>
>
>
> What am I doing wrong, that they’re so different?
>
>
>
> Ronald Phillips, B.S., M.S.
>
> Programmer/Analyst
>
>
>
> Summit County Engineer
>
> 538 E. South St.
>
> Akron OH 44311
>
> 330.643.8061
>
> http://www.linkedin.com/in/rwphillips
>
>
>
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