See: http://www.spatialreference.org/ref/epsg/3997/postgis/ for the insert statement to create this projection in Postgis.
For other information about this projection see: http://www.spatialreference.org/ref/epsg/3997/ HTH, Brent Wood --- On Mon, 5/3/10, Mehmet Erkek <[email protected]> wrote: From: Mehmet Erkek <[email protected]> Subject: Re: [postgis-users] Converting UTM to lat/lon using Postgis To: "PostGIS Users Discussion" <[email protected]> Date: Monday, May 3, 2010, 7:50 PM Thank you for the fast answer! Hmm. It looks I don’t have srid 3997 in the DB. =# select srid, srtext, proj4text from spatial_ref_sys where srid=3997; srid | srtext | proj4text ------+--------+----------- (0 rows) select srid, srtext, proj4text from spatial_ref_sys where srtext like '%Dubai%'; srid | srtext | proj4text ------+--------+----------- (0 rows) Could this be related to my postgis installation? I don’t see this srid in spatial_ref_sys.sql which came with postgis installation either. Any idea how I can fix this? ------------------------------------------------------------------- Mehmet ERKEK www.REIDIN.com From: [email protected] [mailto:[email protected]] On Behalf Of Francis Markham Sent: Monday, May 03, 2010 11:09 AM To: PostGIS Users Discussion Subject: Re: [postgis-users] Converting UTM to lat/lon using Postgis Hi Mehmet, When you imported the shapefile, the SRID you are meant to specify is the SRID of the data, not the SRID you want. Since the data is in Dubai Local TM, the SRID is 3997. To get the transformation you want, try the following: select ST_AsText( ST_Transform(centroid(ST_SetSRID(the_geom, 3997)),4326)) from ult.test2 limit 5; Hope that helps, -Francis On 3 May 2010 17:03, Mehmet Erkek <[email protected]> wrote: Hi All, I havea a shape file which I imported it to a table called ‘test2’ (using SRID=4326). I want to get centroids of geometries in lat/lon. Here is what I run: select ST_AsText( ST_Transform(centroid(the_geom),4326)) from ult.test2 limit 5; and what I get: POINT(496597.996430787 2774798.21242881) POINT(496332.629887436 2793339.61534586) POINT(496302.627327975 2793317.82477318) POINT(496305.255261594 2793353.29646291) POINT(496241.538851096 2774826.65593589) So far all is fine except coordinates which are not latitude/longitude My question is : How can I convert/get these coordinates in lat/lon? This what I have in my prj file: PROJCS["Dubai Local Transverse Mercator (DLTM)",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["False_Easting",500000.0],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",55.33333333333334],PARAMETER["Scale_Factor",1.0],PARAMETER["Latitude_Of_Origin",0.0],UNIT["Meter",1.0]] And this is my postgis version: POSTGIS="1.3.6" GEOS="2.2.3-CAPI-1.1.1" PROJ="Rel. 4.7.1, 23 September 2009" USE_STATS I appreciate any help. Thank you. ------------------------------------------------------------------- Mehmet ERKEK www.REIDIN.com This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the email by you is prohibited. Please Consider the Environment Before Printing This Email _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users This message is for the designated recipient only and may contain privileged, proprietary, or otherwise private information. If you have received it in error, please notify the sender immediately and delete the original. Any other use of the email by you is prohibited. Please Consider the Environment Before Printing This Email -----Inline Attachment Follows----- _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
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