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<p>Jochem,</p>
<p>Is "read the spec", the answer you expected ;-) ? I'm afraid
that's the best I have:
<a class="moz-txt-link-freetext" href="http://docs.opengeospatial.org/is/18-010r7/18-010r7.html">http://docs.opengeospatial.org/is/18-010r7/18-010r7.html</a></p>
<p>Regarding indentation, don't worry about that. Write your WKT as
you can in a file and then use "projinfo @your.wkt", and it will
return a nicely reformatted string. But you need to get brackets
right, otherwise the parser will be lost.<br>
</p>
<p>You may also try the PROJJSON encoding as an input and feed it to
"projinfo @your.json" and it will return a WKT, but I'm not sure
it will help you, as it is more oriented to be machine friendly.<br>
</p>
<p>For CRS definitions themselves, it is unlikely you can use the
transformation constructs if you intend to have your CRS in EPSG.
ABRIDGEDTRANSFORMATION is only for BoundCRS, and they are none of
them in EPSG. GEOGTRAN is a Esri WKT specific thing.
COORDINATETRANSFORMATION is for a standalone
CoordinateTransformation object</p>
<p>If your ultimate goal is to provide CRS and coordinate
transformations to EPSG, then you don't need to create WKT. Go to
<a class="moz-txt-link-freetext" href="https://epsg.org/dataset-change-requests.html">https://epsg.org/dataset-change-requests.html</a> and click on the
"Template for data submission" link at the right of the page, and
you'll get an Excel spreadsheet where you'll get a form with the
decomposition of the objects.</p>
<p>Even<br>
</p>
<div class="moz-cite-prefix">Le 05/12/2022 à 13:03, Lesparre, Jochem
via PROJ a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:AM0P192MB04820882DB45F13C62C5A364EF189@AM0P192MB0482.EURP192.PROD.OUTLOOK.COM">
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<p class="MsoNormal">Dear PROJ maillist,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span lang="EN-GB">At a the national
mapping agency of the Netherlands we are responsible for
defining the CRS of European Netherlands and the 3 islands
of the Caribbean Netherlands. We are working on
standardising the official transformations so these can be
added to EPSG and the transformations become available in
PROJ and other software. To perform transformations ourself,
we create cct pipelines. I love the power cct pipelines.
Unfortunately, other applications often expect a WKT string.
For the transformations we added to EPSG, I can copy-paste
the WKT from epsg.org. To experiment with a custom CRS, I
sometimes try to create my own WKT strings. However, these
attempts are not very successful for two reasons.
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Firstly, it takes an
annoying lot of effort get the code indented to make it
readable (the indent plugin in notepad++ only works after
using search and replace to add line breaks) and to keep the
brackets right for valid WKT while editing, before I can
even start to experiment with the rest of the syntax.
<i>Can you recommend a way to make creating WKT easier?</i>
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Secondly, I am quite
confused by the different WKT examples that I find. Some
seem to use different ways to define transformations in WKT
(e.g. ABRIDGEDTRANSFORMATION, GEOGTRAN,
COORDINATEOPERATION).
<i>Can you recommend a way to get started with understanding
WKT?</i> As a geodesist, I am familiar with transformation
methods, so I only need information on how to translate
between this theory and WKT.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-GB">Kind regards, Jochem<o:p></o:p></span></p>
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