Hi Mehmet,<br><br>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:<br>
<br><p class="MsoNormal">select ST_AsText(
ST_Transform(centroid(ST_SetSRID(the_geom, 3997)),4326)) from ult.test2 limit 5;</p>Hope that helps,<br><br>-Francis<br><br><div class="gmail_quote">On 3 May 2010 17:03, Mehmet Erkek <span dir="ltr"><<a href="mailto:merkek@reidin.com">merkek@reidin.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<div link="blue" vlink="purple" lang="EN-US">
<div>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Hi All,</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">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.
</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Here is what I run:</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">select ST_AsText(
ST_Transform(centroid(the_geom),4326)) from ult.test2 limit 5;</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">and what I get:</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">POINT(496597.996430787 2774798.21242881)</p>
<p class="MsoNormal">POINT(496332.629887436 2793339.61534586)</p>
<p class="MsoNormal">POINT(496302.627327975 2793317.82477318)</p>
<p class="MsoNormal">POINT(496305.255261594 2793353.29646291)</p>
<p class="MsoNormal">POINT(496241.538851096 2774826.65593589)</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">So far all is fine except coordinates which are not latitude/longitude
</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"><b><u>My question is : How can I convert/get these
coordinates in lat/lon?</u></b></p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">This what I have in my prj file: </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">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]]</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">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</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">I appreciate any help. Thank you.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"><span style="font-size: 8pt; color: rgb(15, 36, 62);">-------------------------------------------------------------------</span></p>
<p class="MsoNormal"><b><span style="font-size: 8pt; color: rgb(15, 36, 62);">Mehmet ERKEK</span></b><b></b></p>
<p class="MsoNormal"><span style="font-size: 8pt; color: rgb(15, 36, 62);"><a href="http://www.reidin.com/" target="_blank"><span style="color: rgb(15, 36, 62);">www.REIDIN.com</span></a></span></p>
<p class="MsoNormal"> </p>
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