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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Mystery solved – at least the
initial part – My GDAL / OGR build does not have Proj4 included as a
static library and I did not have the DLL in the execution path.</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Is there a way to query OGR to get an
error message or code that explains why an operation fails?</span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'> </span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Bruce</span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'> gdal-dev-bounces@lists.osgeo.org
[mailto:gdal-dev-bounces@lists.osgeo.org] <b><span style='font-weight:bold'>On
Behalf Of </span></b>Clay, Bruce<br>
<b><span style='font-weight:bold'>Sent:</span></b> Wednesday, March 12, 2008
5:33 PM<br>
<b><span style='font-weight:bold'>To:</span></b> gdal-dev@lists.osgeo.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> [gdal-dev] Create
Coordinate Transformation always returns NULL</span></font></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I am trying to create a transformation from WGS 84 to a
projected system. I have tried several but create transform always
returns NULL.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The code I am using is essentially the reverse sequence as
shown in the OSR tutorial. That is that the example went from a projected
frame to a geodetic frame.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>The returned status for each of the steps is 0 so it looks
like everything should work and this type of transform is fairly common so I
would think it should be supported by proj4 but I don’t see anything in
the proj4 docs that describe what types are supported.</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Any ideas would be greatly appreciated</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Bruce</span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 color=green
face="Courier New"><span Courier><span style='font-size:10.0pt;font-family:
"Courier New";color:green'>///////////////////////////////////////////////////////////////////////////////</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>OGRCoordinateTransformation
*GdalWrapper::CreateWellKnownTransformation(</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
<font color=blue><span style='color:blue'>const</span></font> <font color=blue><span
style='color:blue'>char</span></font> *srcWngcsSrs, <font color=blue><span
style='color:blue'>const</span></font> <font color=blue><span style='color:
blue'>char</span></font> *destWngcsSrs)</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>{</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
<font color=blue><span style='color:blue'>int</span></font> status = -1;</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
OGRErr ogrStatus;</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
OGRCoordinateTransformation *coordTransPtr = NULL;</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'> </span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
OGRSpatialReference srcSpatialRef;</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
OGRSpatialReference destSpatialRef;</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'> </span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
ogrStatus = srcSpatialRef.SetWellKnownGeogCS(<font color=maroon><span
style='color:maroon'>"WGS84"</span></font>);</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'> </span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
<font color=blue><span style='color:blue'>if</span></font> (ogrStatus == 0)</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
{</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
ogrStatus = destSpatialRef.SetProjCS(<font color=maroon><span style='color:
maroon'>"UTM 17 / WGS84"</span></font> );</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
ogrStatus = destSpatialRef.SetWellKnownGeogCS( <font color=maroon><span
style='color:maroon'>"WGS84"</span></font> );</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
ogrStatus = destSpatialRef.SetUTM( 17, TRUE );</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'> </span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
<font color=blue><span style='color:blue'>if</span></font> (ogrStatus == 0)</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
{</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
coordTransPtr = OGRCreateCoordinateTransformation(</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
&srcSpatialRef, &destSpatialRef);</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
}</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
}</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>
<font color=blue><span style='color:blue'>return</span></font>(coordTransPtr);</span></span></font></p>
<p class=MsoNormal style='text-autospace:none'><font size=2 face="Courier New"><span
Courier><span style='font-size:10.0pt;font-family:"Courier New"'>}</span></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> </span></font></p>
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