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<p class="MsoNormal">I am experiencing errors when I try to use ST_Transform to convert points from projections using NAD27 to NAD83, and vice versa. I don’t receive any errors back when I run ST_Transform, but the coordinates that are returned are incorrect.
The amount by which they are off (about 50 meters) is the amount of error I would expect with an incorrectly specified datum, so I am fairly certain that PostGIS is not transforming between NAD27 and NAD83, and vice versa.
<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">----go from dd NAD83 to dd NAD27<o:p></o:p></p>
<p class="MsoNormal"><i>SELECT ST_X(ST_TRANSFORM(ST_SETSRID(ST_MAKEPOINT(-107.074497916,42.9399159501),4267),4152)),ST_Y((ST_TRANSFORM(ST_SETSRID(ST_MAKEPOINT(-107.074497916,42.9399159501),4267),4152)));</i><o:p></o:p></p>
<p class="MsoNormal">--should return -107.073884255, 42.9399531071 (or so), but actually returns -107.074497916,42.939915951<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I get the same scale of error when trying to go between UTM Zone 13 NAD83 and UTM Zone 13 NAD27 – it’s basically just giving me back the same coordinates that go in, without doing the datum transformation.<i><o:p></o:p></i></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">SELECT Postgis_full_version() returns:<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">postgis_full_version<o:p></o:p></p>
<p class="MsoNormal"><i>POSTGIS="2.2.1 r14555" GEOS="3.4.2-CAPI-1.8.2 r3921" PROJ="Rel. 4.8.0, 6 March 2012" GDAL="GDAL 1.9.2, released 2012/10/08" LIBXML="2.9.1" RASTER<o:p></o:p></i></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">What am I missing?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="border:none;padding:0in"><b><span style="font-size:12.0pt;font-family:"Cambria",serif"><o:p> </o:p></span></b></p>
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<p class="MsoNormal"><b><span style="font-size:12.0pt;font-family:"Cambria",serif"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:12.0pt;font-family:"Cambria",serif">Mark D. Andersen<o:p></o:p></span></b></p>
<p class="MsoNormal"><i><span style="font-size:12.0pt;font-family:"Cambria",serif">Spatial Ecologist // GIS Analyst<o:p></o:p></span></i></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Cambria",serif"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><i><span style="font-size:12.0pt;font-family:"Cambria",serif;color:#1F497D"><a href="http://uwadmnweb.uwyo.edu/wyndd/"><span style="color:#1F497D">Wyoming Natural Diversity Database</span></a><o:p></o:p></span></i></b></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Cambria",serif">University of Wyoming<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Cambria",serif">Department 3381 // 1000 E. University Ave.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Cambria",serif">Laramie, Wyoming 82071<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Cambria",serif">PHONE: 307 766 3036<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Cambria",serif">FAX: 307 766 3026<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Cambria",serif">EMAIL:
<span style="color:#1F497D"><a href="mailto:mda@uwyo.edu"><span style="color:#1F497D">mda@uwyo.edu</span></a></span><o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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