<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40"><head><meta http-equiv=Content-Type content="text/html; charset=utf-8"><meta name=Generator content="Microsoft Word 14 (filtered medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0cm;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
span.EmailStyle17
{mso-style-type:personal;
font-family:"Calibri","sans-serif";
color:#1F497D;}
span.EmailStyle18
{mso-style-type:personal;
font-family:"Courier New";
color:#1F497D;}
span.EmailStyle19
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:612.0pt 792.0pt;
margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]--></head><body lang=EN-AU link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks for all the suggestions – they have given me many possibilities to eliminate, but I still haven’t really got an answer to the original question.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Am I required to have proj.dll built with support for the datums/projections I want to use, or is it sufficient to set GDAL_DATA such that gcs.csv and pcs.csv are visible? I’m working in VB.NET, and I’m not confident I can rebuild PROJ with the required datums, so I wish to avoid if possible. I’d even be prepared to use SetGeogCS explicitly as I only use a few datums. If I use SetGeogCS, I can’t see what purpose proj.dll serves.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I have set GDAL_DATA to the correct folder.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I have checked that the datum numbers I use are in the gcs.csv file.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Courier New";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> gdal-dev-bounces@lists.osgeo.org [mailto:gdal-dev-bounces@lists.osgeo.org] <b>On Behalf Of </b>dev4cx4m9z@snkmail.com<br><b>Sent:</b> Tuesday, October 18, 2011 4:12 AM<br><b>To:</b> gdal-dev@lists.osgeo.org<br><b>Subject:</b> RE: [gdal-dev] Confused about datum transformations<o:p></o:p></span></p></div></div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal style='text-autospace:none'>I’m not sure the code will help too much, but here are the relevant code fragments. I’m using a hand crafted VB.net wrapper which explains some of the syntax<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'>Private WGS84SRS As New OGRSpatialReference ' Coordinate system in WGS84<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'>Private MapSRS As OGRSpatialReference ' Coordinate system of map<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'>Private ctWGS84toMap As OGRCoordinateTransformation ' Coordinate transform from WGS84 to map<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'>With WGS84SRS<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'> GDALError = .SetProjCS("WGS84 Datum")<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'> Debug.Assert(GDALError = OGRError.OGRERR_NONE, GetLastErrorMsg())<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'> GDALError = .SetWellKnownGeogCS("WGS84") ' Define WGS84 coordinate system<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'> Debug.Assert(GDALError = OGRError.OGRERR_NONE, GetLastErrorMsg())<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'>End With<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'>With MapSRS<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'> GDALError = .SetProjCS("Map coordinate system")<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'> Debug.Assert(GDALError = OGRError.OGRERR_NONE, GetLastErrorMsg())<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'> GDALError = .ImportFromEPSG(3577)<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'> Debug.Assert(GDALError = OGRError.OGRERR_NONE, GetLastErrorMsg())<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'>End With<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'>ctWGS84toMap = GDAL.CreateCoordinateTransformation(WGS84SRS, MapSRS) ' Create a coordinate transformation - WGS84 to map<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'>Debug.Assert(ctWGS84toMap IsNot Nothing, GetLastErrorMsg())<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='margin-bottom:12.0pt'>Marc,<br><br>Can you provide the code leading to the error?<o:p></o:p></p><div><p class=MsoNormal>On Tue, Oct 18, 2011 at 1:21 PM, Marc Hillman <<a href="mailto:dev4cx4m9z@snkmail.com">dev4cx4m9z@snkmail.com</a>> wrote:<o:p></o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>I have a GIS database, and all data is stored in WGS84 datum. I have developed an application using GDAL, and I now need to translate my WGS84 coordinates to several different datums, depending what map is loaded. I seem to be going around in circles, and need a nudge in the right direction. I am defining an OGRSpatialReference for each datum (WGS84 and current map) and then attempting to create an OGRCoordinateTransformation for the transformation.. This last step fails with a PROJ.4 error (“No PROJ.4 translation for destination SRS, coordinate transformation initialization failed”<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>My question is - Do I need PROJ.4 to do the translation? Can I not just use ImportFromWKT to define my OGRSpatialReference? If so, is there a nice canned list of all the WKT somewhere? I’m keen to avoid PROJ.4 if possible as I’m not sure I can build it.<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> <o:p></o:p></p></div></div><p class=MsoNormal><br>_______________________________________________<br>gdal-dev mailing list<br><a href="mailto:gdal-dev@lists.osgeo.org">gdal-dev@lists.osgeo.org</a><br><a href="http://lists.osgeo.org/mailman/listinfo/gdal-dev" target="_blank">http://lists.osgeo.org/mailman/listinfo/gdal-dev</a><o:p></o:p></p></div><p class=MsoNormal style='margin-bottom:12.0pt'><br><br clear=all><br>-- <br>Best regards,<br>Chaitanya kumar CH.<br><br>+91-9494447584<br>17.2416N 80.1426E<o:p></o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>No virus found in this message.<br>Checked by AVG - <a href="http://www.avg.com">www.avg.com</a><br>Version: 2012.0.1831 / Virus Database: 2092/4558 - Release Date: 10/17/11<o:p></o:p></p><p class=MsoNormal><span lang=EN-US><br>This email message is for the sole use of the intended recipient(s) and may contain confidential and privileged information. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply email and delete the original message. <o:p></o:p></span></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>No virus found in this message.<br>Checked by AVG - <a href="http://www.avg.com">www.avg.com</a><br>Version: 2012.0.1831 / Virus Database: 2092/4558 - Release Date: 10/17/11<o:p></o:p></p></div></body></html>