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<p>Johem,</p>
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<p class="MsoNormal">Why the differences, and is there a correct
way?</p>
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Both ways are correct. PROJ is supposed to follow the
recommendations given at paragraph 7.3.3 Identifier of
<a class="moz-txt-link-freetext" href="https://docs.ogc.org/is/18-010r11/18-010r11.pdf">https://docs.ogc.org/is/18-010r11/18-010r11.pdf</a> where there are lots
of rules for when it is recommended to include or omit identifiers.<br>
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<p class="MsoNormal"><o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">It seems to me that most of the information
is redundant anyway, just the EPSG code could do: e.g.
COMPOUNDCRS["Bonaire DPnet + Bonaire
height",ID["EPSG",10764]]. What elements are mandatory and
what not? </p>
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This is defined in the above mentionned WKT CRS standard.<br>
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<p class="MsoNormal">This is relevant to me because we might
want to change the CONVERSION of some PROJCRSs in EPSG in the
future without changing the ID of the PROJCRS. Omitting the
CONVERSION and only mentioning the ID of the PROJCRS in the
WKT therefore seems a saver choice for the metadata of
geo-information. Is this allowed?</p>
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<p>No. The idea of WKT CRS is that you should be able to make sense
of the definition without a geodetic database available. At least
for the purpose of doing geographic <--> projected
coordinate conversions (in the same datum)<br>
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Even<span style="white-space: pre-wrap">
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<pre class="moz-signature" cols="72">--
<a class="moz-txt-link-freetext" href="http://www.spatialys.com">http://www.spatialys.com</a>
My software is free, but my time generally not.</pre>
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