<div dir="ltr">I was thinking on a WKT that defines the offset as part of the CRS defintion, in a similar way the geoid grid file can be defined.<br clear="all"><div><div><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature">.___ ._ ..._ .. . ._. .___ .. __ . _. . __.. ... .... ._ .__<br>Entre dos pensamientos racionales <br>hay infinitos pensamientos irracionales.<br><br></div></div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, 29 Nov 2021 at 17:05, Even Rouault <<a href="mailto:even.rouault@spatialys.com">even.rouault@spatialys.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<p>Javier,</p>
<p>If you need a WKT2 with a coordinate operation, then you can
simply wrap any PROJ string expressing a coordinate operation like
the following:<br>
</p>
<p>$ projinfo "+proj=geogoffset +dh=5" -o WKT2:2019 -q<br>
<br>
CONVERSION["PROJ-based coordinate operation",<br>
METHOD["PROJ-based operation method: +proj=geogoffset +dh=5"]]<br>
</p>
<p>Of course only interoperable in the PROJ universe.</p>
<p>Otherwise using Transformation::createGeographic3DOffsets() /
createGeographic2DWithHeightOffsets() could have been an option,
but if your source and target CRS aren't geographic, PROJ will
complain when getting the PROJ transformation string.<br>
</p>
<p>Even<br>
</p>
<div>Le 29/11/2021 à 16:53, Javier Jimenez
Shaw a écrit :<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>Thanks Even</div>
<div><br>
</div>
<div>Is there anything equivalent to that as Vertical CRS to use
in a Compound? I know it is not correct geodetically, but I
want it just as a WKT temporary object. I just need that PROJ
is able to understand it and use it in a transformation.<br>
</div>
<div>That is, given a horizontal CRS, I want to create a
compound (or anything equivalent) with a vertical offset (as
WKT2 if it makes things easier)</div>
<div><br>
</div>
<div>Thanks.<br>
</div>
<div>
<div>
<div dir="ltr">.___ ._ ..._ .. . ._.
.___ .. __ . _. . __.. ... .... ._ .__<br>
Entre dos pensamientos racionales <br>
hay infinitos pensamientos irracionales.<br>
<br>
</div>
</div>
<br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Mon, 1 Nov 2021 at 17:01,
Even Rouault <<a href="mailto:even.rouault@spatialys.com" target="_blank">even.rouault@spatialys.com</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>
<p>Javier<br>
</p>
<div>Le 01/11/2021 à 13:32, Javier Jimenez Shaw a écrit :<br>
</div>
<blockquote type="cite">
<div dir="ltr">
<div>Hi</div>
<div><br>
</div>
<div>I want to make a transformation (at the end an
operation::CoordinateOperation) that replaces the
geoid model with a local constant value.</div>
<div><br>
</div>
<div>In some cases there is public grid file for a geoid
model, but I can get a (constant) undulation value
(let's say 42.9m) in a (small) area of work. I would
like to include this undulation value in the
transformation.</div>
<div><br>
</div>
<div>How can I do that? is there any pipeline option for
that? (I do not see a way in <a href="https://proj.org/operations/transformations/vgridshift.html" target="_blank">https://proj.org/operations/transformations/vgridshift.html</a>)
Or a way to directly create the CoordinateOperation?</div>
</div>
</blockquote>
<p>You can use the <a href="https://proj.org/operations/transformations/geogoffset.html" target="_blank">https://proj.org/operations/transformations/geogoffset.html</a>
with the dh parameter. This is for example used for
transformation EPSG:15596<br>
</p>
<p>Even<br>
</p>
<blockquote type="cite">
<div dir="ltr">
<div><br>
</div>
<div>Thanks<br>
</div>
<div>
<div>
<div dir="ltr">.___ ._ ..._ .. . ._. .___ .. __ .
_. . __.. ... .... ._ .__<br>
Entre dos pensamientos racionales <br>
hay infinitos pensamientos irracionales.<br>
<br>
</div>
</div>
</div>
</div>
<br>
<fieldset></fieldset>
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</blockquote>
</div>
</blockquote>
<pre cols="72">--
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</blockquote></div>