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<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">I guessed so. Is that your own invention or is it documented somewhere that undefined GCPs should be marked that way by using INF? I ask because if it is something that should be reliable
then I may have use for that feature in the future.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">Problem may be limited to vrt. This test seems to pass<br>
<br>
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">gdal_translate -gcp 0 0 inf inf test.tif inftest.tif<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">gdalinfo inftest.tif<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">…<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">GCP[ 0]: Id=1, Info=<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"> (0,0) -> (inf,inf,0)
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US">-Jukka Rahkonen-<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="mso-fareast-language:EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US">Lähettäjä:</span></b><span lang="EN-US"> Pierluigi Guasqui <guasqui@actgate.com>
<br>
<b>Lähetetty:</b> torstai 25. tammikuuta 2024 14.16<br>
<b>Vastaanottaja:</b> Rahkonen Jukka <jukka.rahkonen@maanmittauslaitos.fi><br>
<b>Aihe:</b> Re: [gdal-dev] Bad values when reading GCPs from a VRT file with gdalinfo in GDAL 3.8.3<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">Hello Jukka,<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">in general using infinite values is to mark undefined or invalid GCPs.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">Pierluigi<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">On Thu, Jan 25, 2024 at 12:44 PM Rahkonen Jukka <</span><a href="mailto:jukka.rahkonen@maanmittauslaitos.fi"><span lang="EN-US">jukka.rahkonen@maanmittauslaitos.fi</span></a><span lang="EN-US">> wrote:<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Out of curiosity, what is the purpose of using inf or -inf as values? Is it to use them as placeholders telling that you do not know yet what the georeferenced
coordinates of the ground control points are?<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">-Jukka Rahkonen-<o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span lang="EN-US">Lähettäjä:</span></b><span lang="EN-US"> gdal-dev <</span><a href="mailto:gdal-dev-bounces@lists.osgeo.org" target="_blank"><span lang="EN-US">gdal-dev-bounces@lists.osgeo.org</span></a><span lang="EN-US">>
<b>Puolesta </b>Pierluigi Guasqui via gdal-dev<br>
<b>Lähetetty:</b> torstai 25. tammikuuta 2024 13.34<br>
<b>Vastaanottaja:</b> </span><a href="mailto:gdal-dev@lists.osgeo.org" target="_blank"><span lang="EN-US">gdal-dev@lists.osgeo.org</span></a><span lang="EN-US"><br>
<b>Aihe:</b> [gdal-dev] Bad values when reading GCPs from a VRT file with gdalinfo in GDAL 3.8.3<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Dear GDAL team,<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">I am using GDAL version 3.8.3 and I am trying to extract GCPs values with gdalinfo tool from a VRT file (attached).<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">As you can see by looking at the VRT file with a text editor GCP XYZ values are infinite values. When I read GCPs from the attached VRT file with gdalinfo (latest
version GDAL v. 3.8.3) I am getting all zeros:<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-family:"Courier New"">GCP[ 0]: Id=0, Info=<br>
(0,0) -> (0,0,0)</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-family:"Arial",sans-serif">Instead, if I use gdalinfo (GDAL v. 3.6.3) I am getting the correct values:</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-family:"Courier New"">GCP[ 0]: Id=0, Info=<br>
(0,0) -> (inf,inf,-inf)</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Is this a bug with GDAL 3.8.3?<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> <o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Thank you for your help!<o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"><br>
<span class="m-916595110531667051gmailsignatureprefix">-- </span><o:p></o:p></span></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Pierluigi Guasqui<br>
Software Engineer<br>
<br>
Applied Coherent Technology Corporation (ACT)<br>
</span><a href="http://www.actgate.com/" target="_blank"><span lang="EN-US">www.actgate.com</span></a><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><br clear="all">
<br>
<span class="gmailsignatureprefix">-- </span><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">Pierluigi Guasqui<br>
Software Engineer<br>
<br>
Applied Coherent Technology Corporation (ACT)<br>
</span><a href="http://www.actgate.com/" target="_blank"><span lang="EN-US">www.actgate.com</span></a><span lang="EN-US"><o:p></o:p></span></p>
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