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<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">Hi Even,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">then I understand that CreateField() is the only thing that can create the fields and that call to this function stablish the number of fields for ALL EXISTING features at the moment of being called?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">Thanks for the explanations. I’ll thing if it’s easy to support that or it’s better to error out this.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">Abel<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span lang="EN-US" style="mso-fareast-language:CA">De:</span></b><span lang="EN-US" style="mso-fareast-language:CA"> Even Rouault <even.rouault@spatialys.com>
<br>
<b>Enviado el:</b> dilluns, 2 d’octubre de 2023 17:36<br>
<b>Para</b></span><b><span lang="ES" style="mso-fareast-language:CA">:</span></b><span lang="ES" style="mso-fareast-language:CA"> Abel Pau <a.pau@creaf.uab.cat>; gdal dev <gdal-dev@lists.osgeo.org><br>
<b>Asunto:</b> Re: [gdal-dev] Number of fields when creating layer?<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p><o:p> </o:p></p>
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<p class="MsoNormal">Le 02/10/2023 à 17:23, Abel Pau a écrit :<o:p></o:p></p>
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<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><span lang="ES" style="color:#1F497D">Thanks Even,</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="ES" style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">that it’s not so bad. I can “wait” until ICreateFeature and if it’s the first feature create the number of fields it has.</span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">But, then, what happens with other fields that can appear after in next features? I might ignore them, but... it’s not a good thing.
</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif;mso-fareast-language:CA">Just look at existing drivers, like the JML one I pointed. They will error out when attempting to call CreateField() once a feature has been written,
and they will stop advertizing the OLCCreateField capability as well.<br>
<br>
<o:p></o:p></span></p>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D"> </span><o:p></o:p></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#1F497D">Can they appear later or not? I haven’t understood it at complete.</span><o:p></o:p></p>
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<p>Calling CreateField() at any time is a possibility of the OGR API. That doesn't mean that all drivers have to support it. Most writers will generally create all needed fields before writing features, if they can, to be compatible with as many output drivers
as possible.<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif;mso-fareast-language:CA"><br>
<br>
<o:p></o:p></span></p>
<pre>-- <o:p></o:p></pre>
<pre><a href="http://www.spatialys.com">http://www.spatialys.com</a><o:p></o:p></pre>
<pre>My software is free, but my time generally not.<o:p></o:p></pre>
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