Aren't they using CHTRS95 ? https://epsg.org/crs_4933/CHTRS95.html
On Wed, 18 Sept 2024 at 11:53, Lesparre, Jochem <jochem.lespa...@kadaster.nl> wrote: > > > > Looking at the pipelines, the steps would be ITRF2020 -> ETRF2020 -> > ETRS89 -> CH1903+ > > > > I am pretty sure Switzerland uses ETRF2000 as ETRS89 realisation, not > ETRF2020. So, the correct transformation would be: > > > > ITRF2020 -> ETRF2000 -> ETRS89 -> CH1903+ > > > > The difference between ETRF2000 and ETRF2020 is about 7 cm. ETRF2000 is > recommended for use by national mapping agencies. > > > > Jochem > > > > > > *From:* PROJ <proj-boun...@lists.osgeo.org> *On Behalf Of *Javier Jimenez > Shaw via PROJ > *Sent:* dinsdag 27 augustus 2024 19:30 > *To:* proj <PROJ@lists.osgeo.org> > *Subject:* [PROJ] Transformations in ITRF2020 > > > > Hi > > > > I am now facing transformations with ITRF2020 with time(yes, because > Skylark, but I guess more NTRIPs are going to do (or already doing) the > same) > > > > The point is when the destination CRS does not have a direct > transformation from ITRF2020 (or almost). > > > > For instance, EPSG:4150, CH1903+ (the geographic of LV95, in Switzerland) > is only connected to ETRS89. See that CH1903+ is in the European tectonic > plate, as ETRS89 > > > > A direct transformation is completely ballpark > > > > echo 42 6 0 2024.6 | ./cs2cs EPSG:9989 EPSG:4150 -d 9 --3d > 42.000000000 6.000000000 0.000000000 2024.6 > > > > However, from ITRF2020 to ETRS89 there is some change due to the time (the > European plate moving at 2.5 cm/a since 2015): > > echo 42 6 0 2024.6 | ./cs2cs EPSG:9989 EPSG:4937 -d 9 --3d > 41.999994981 5.999991317 -0.001861237 2024.6 > > > > and from ETRS89 to CH1903+ due to the datum offset: > echo 42 6 0 2024.6 | ./cs2cs EPSG:4937 EPSG:4150 -d 9 --3d > 42.000742733 6.000670188 -60.682799297 2024.6 > > > > Looking at the pipelines, the steps would be ITRF2020 -> ETRF2020 -> > ETRS89 -> CH1903+ > > (btw, only since PROJ 9.4.1, when ETRF2020 was added) > > > > I understand that the only way to get the proper transformation is > chaining these two manually. Via ETRS89 ... because I know it. Right? > > > > Well, the future does not look so promising to me: in EPSG I only see > transformations from ITRF2020 to ETRF family, NAD83(2011) family and > NAD83(CSRS)v8. That is Europe, USA and Canada. That's all, folks. > > > > Thanks, > > .___ ._ ..._ .. . ._. .___ .. __ . _. . __.. ... .... ._ .__ > > Javier Jimenez Shaw > > Mercator str 42. > > Null-Island > > > Disclaimer: > De inhoud van deze e-mail is vertrouwelijk en uitsluitend bestemd voor de > geadresseerde(n). > Gebruik, openbaarmaking, vermenigvuldiging, verspreiding en/of > verstrekking van deze informatie aan derden is niet toegestaan. > Op al onze producten en diensten zijn onze algemene leveringsvoorwaarden > van toepassing > [https://www.kadaster.nl/algemene-leveringsvoorwaarden]. > > Disclaimer: > This email and any files transmitted with it are confidential and intended > solely for the use of the individual or entity to whom they are addressed. > If you are not the intended recipient, you are notified that disclosing, > copying, distributing or taking any action in reliance on the contents of > this information is strictly prohibited. > Our general terms and conditions of delivery apply to all our products and > services > [https://www.kadaster.com/general-terms-and-conditions]. >
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