Frank (and all):<br><br>Thanks for the information. Using this link:<br><br><a href="http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/tolatlong.py" target="_blank">http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/tolatlong.py</a><br>
<br>I was able to figure out how to transform points from one EPSG coordinate system to another using Python. Here's how:<br><br>#transform()<br>def transform(i_srs, o_srs, lon, lat):<br> # i_srs looks like "EPSG:4326"<br>
# o_srs looks like "EPSG:3338"<br> <br> from osgeo import osr<br> <br> i_num = int(i_srs.split(':')[1]) #obtain the EPSG number<br> o_num = int(o_srs.split(':')[1]) #obtain the EPSG number<br>
<br> srs_in = osr.SpatialReference() #create an input Spatial Reference<br> srs_in.ImportFromEPSG(i_num) #import from EPSG:4326<br> <br> srs_out = osr.SpatialReference() #create an output Spatial Reference<br>
srs_out.ImportFromEPSG(o_num) #import from EPSG:3338<br> <br> ct = osr.CoordinateTransformation(srs_in, srs_out) #CoordinateTransformation object from EPSG:4326 to EPSG:3338<br> (X, Y, height) = ct.TransformPoint(float(lon), float(lat)) #Calculate our transformed points<br>
<br> return (X, Y, height)<br>#the returned values give exactly what is expected as per my previous email<br>#end of script<br><br>Thanks again everyone!<br><br>Jon<br><br><div class="gmail_quote">On Fri, Aug 21, 2009 at 6:03 PM, Frank Warmerdam <span dir="ltr"><<a href="mailto:warmerdam@pobox.com">warmerdam@pobox.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 class="im">Jonathan Sawyer wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Good evening developers,<br>
<br>
I am very new to GDAL, so please bear with me.<br>
<br>
What function/class/module do I need to look at to perform coordinate transformation, in Python?<br>
<br>
Or better yet, can anyone point me to good online docs to learn how the Python bindings are used in gdal?<br>
<br>
FYI: I am looking for the equivalent to this command line example:<br>
<br>
$ gdaltransform -s_srs EPSG:4326 -t_srs EPSG:3338<br>
-146.673599867, 64.7163624865<br>
348408.577415968 1658661.40355536 0<br>
<br>
Have a good weekend, and thanks for your help.<br>
</blockquote>
<br></div>
Jonathan,<br>
<br>
There are some pointers to sample python scripts at:<br>
<br>
<a href="http://trac.osgeo.org/gdal/wiki/GdalOgrInPython" target="_blank">http://trac.osgeo.org/gdal/wiki/GdalOgrInPython</a><br>
<br>
The tolatlong.py script has some example script for transforming<br>
points:<br>
<br>
<a href="http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/tolatlong.py" target="_blank">http://svn.osgeo.org/gdal/trunk/gdal/swig/python/samples/tolatlong.py</a><br>
<br>
Good luck,<br><font color="#888888">
-- <br>
---------------------------------------+--------------------------------------<br>
I set the clouds in motion - turn up | Frank Warmerdam, <a href="mailto:warmerdam@pobox.com" target="_blank">warmerdam@pobox.com</a><br>
light and sound - activate the windows | <a href="http://pobox.com/%7Ewarmerdam" target="_blank">http://pobox.com/~warmerdam</a><br>
and watch the world go round - Rush | Geospatial Programmer for Rent<br>
<br>
</font></blockquote></div><br><br clear="all"><br>-- <br>Jonathan Sawyer<br>Geographic Information Network of Alaska (GINA)<br>University of Alaska Fairbanks<br>