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<p>Javier,</p>
<p>Regarding intra-ITRF transformations, the EPSG database lacks the
ITRF plate motion models. We do have them (up to ITRF2014) in the
data/ITRFxxxx files (cf the link to a previous thread of mine that
Jack Riley has quoted). I see we don't have yet the ITRF2020 ones.
They are at
<a class="moz-txt-link-freetext" href="https://itrf.ign.fr/docs/solutions/itrf2020/ITRF2020-PMM.dat">https://itrf.ign.fr/docs/solutions/itrf2020/ITRF2020-PMM.dat</a></p>
<p>For a fully automated solution what would be mostly missing in
PROJ is support for non-rectangular area of interest, as the
rectangular model could be very inadequate for parts of the world</p>
<p>Even<br>
</p>
<div class="moz-cite-prefix">Le 23/08/2024 à 11:28, Javier Jimenez
Shaw via PROJ a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:CADRrdKtyZMLVSjY7JFEE6uL0xmhXKpw8tBLKhGhnw+HsQ_b=dQ@mail.gmail.com">
<div dir="ltr">
<div>Hi</div>
<div><br>
</div>
<div>I am a bit confused with the epoch of coordinates. For
instance, if I connect to this NTRIP service <br>
</div>
<div><a
href="https://support.swiftnav.com/support/solutions/articles/44002386941-configuring-your-receiver"
moz-do-not-send="true" class="moz-txt-link-freetext">https://support.swiftnav.com/support/solutions/articles/44002386941-configuring-your-receiver</a></div>
<div>it says explicitly that "Skylark Nx RTK uses ITRF2020
reference frame."</div>
<div>Does it mean that the coordinates that I measure today do
have an epoch of 2024.x (today's epoch), or the epoch of those
measurements is 2015.0 (the epoch of ITRF2020 <a
href="https://epsg.org/datum_1322/International-Terrestrial-Reference-Frame-2020.html"
moz-do-not-send="true" class="moz-txt-link-freetext">https://epsg.org/datum_1322/International-Terrestrial-Reference-Frame-2020.html</a>)</div>
<div><br>
</div>
<div>If I want to transform from that reference system
(ITRF2020) to, let's say, ETRS89 or NAD83(2011), should I add
an epoch? which one? where? what happens if I do not set any?<br>
</div>
<div><br>
</div>
<span>I have the impression that I could convert from one epoch
to another for the same CRS, something like this</span>
<div><span>PROJ_DATA=data ./bin/projinfo -s EPSG:9989 -t
EPSG:9989 --s_epoch 2015.0 --t_epoch 2020.0 -o proj<br>
Candidate operations found: 1<br>
-------------------------------------<br>
Operation No. 1:<br>
<br>
unknown id, Null geographic offset from ITRF2020 to
ITRF2020, 0 m, World.<br>
<br>
PROJ string:<br>
+proj=noop</span></div>
<div><br>
</div>
<div>... but it does not. Should it do a non noop
transformation?</div>
<div><br>
</div>
<div>Note: s_epoch and t_epoch were added in PROJ 9.4</div>
<div><br>
</div>
<div>Thanks.</div>
<div><br>
</div>
<div><br>
</div>
<div>PS. ITRF2020 to CH1903+ is a complete ballpark :(<br>
</div>
<div>
<div>
<div>
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<div>.___ ._ ..._ .. . ._. .___ .. __ . _. . __..
... .... ._ .__</div>
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<br>
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</blockquote>
<pre class="moz-signature" cols="72">--
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My software is free, but my time generally not.</pre>
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