# dealing with 2 different coordination systems in postGIS

I'm seeking a function that converts degrees to the following format:

``````POINT(405115.926025391 4543389.4354248)
``````

I dont know this format's name, but is there any function to do so?

Cheers,

EDIT ------- > converting SRID

``````WITH currentPoint AS (
SELECT
st_transform(st_setsrid(st_makepoint(3.6392182823950043, 37.74446159789074), 900913), 900913) AS point
)
SELECT
building.gid
FROM
building, currentPoint
WHERE
ST_Dwithin(building.geom, currentPoint .point, 10)
``````
-

There's two obvious errors:

``````st_transform(st_setsrid(st_makepoint(3.6392182823950043, 37.74446159789074), 900913), 900913) AS point
``````

It seems, you want to convert from 4326 to 900913, so you have to: 1) create point with ST_MakePoint 2) set it's SRID to 4326 with ST_SetSRID 3) Transform it to 900913 with ST_Transform

``````st_transform(st_setsrid(st_makepoint(3.6392182823950043, 37.74446159789074), 4326), 900913) AS point
``````

Probably it's typo (extra space) in

``````ST_Dwithin(building.geom, currentPoint .point, 10)
``````

and you mean

``````ST_Dwithin(building.geom, currentPoint.point, 10)
``````

BTW, you are looking for buildings, that are within 10 SRID units (lets say 10 meters, to keep things simple) from given point, that's quite a small distance.

-

i dont know but it looks like SRID EPSG:900913 - Google Map Web Mercator.

you can try this:

``````UPDATE myTable SET  the_geom = ST_Transform(the_geom,900913);

SELECT UpdateGeometrySRID('myTable', 'the_geom', 900913);
``````

i have tested your coordinates in any openlayers page with using this and it gives me this result:

``````new OpenLayers.Geometry.Point(405115.926025391, 4543389.4354248)
.transform(new OpenLayers.Projection('EPSG:900913'), new OpenLayers.Projection('EPSG:4326'));
``````

the returned result:

``````POINT(3.6392182823950043 37.74446159789074) { id=
"OpenLayers_Geometry_Point_865"
, x=
3.6392182823950043
, y=
37.74446159789074
, more...}
``````

i hope it helps you...

-
thanks Aragon for quick response, now this is what I get "transform: couldn't project point" – Kourosh Dec 3 '12 at 15:39
check out if you have EPSG:900913 in your spatial_ref. `SELECT proj4text FROM spatial_ref_sys WHERE srid = 900913`; – Aragon Dec 3 '12 at 15:46
yes, I do have this SRID, I've updated my question based on your answer, but still not on the right path, cause I get error, am I making an obvious mistake? thanks – Kourosh Dec 3 '12 at 15:57
You need to define your starting point as SRID 4326 and convert it to 900913. It looks like you're doing it the other way around. – Mintx Dec 3 '12 at 18:30