<div dir="ltr"><div>Hi list,</div><div>I have started playing a bit with some Vertical
CRS transformations and I'm trying to figure out how they works so sorry
in advance if I ask something obvious.</div><div><br></div><div>I have installed PROJ 7.0.0 on an Ubuntu 19.10 using conda and I have configured the PROJ_LIB to point to the 2 directories:</div><div><br></div><div>proj-data-1.0-1/share/proj <br></div><div>as well as <br></div><div>proj-7.0.0/share/proj</div><div><br></div><div>so that it should find all the needed definitions.</div><div>Moreover I have also copied there a couple of .csv and grid***.tif to extend the EPSG list.</div><div><br></div><div>Then, I started some sample calls to figure out how it works:</div><div>projinfo -s "EPSG:5778" -t "EPSG:9274"</div><div><br></div><div>It reports "Candidate operations found: 2"</div><div>But for the second one I see this message:</div><div><br></div><div>Operation No. 2:<br>EPSG:9275, GHA height to EVRF2000 Austria height (1), 0.05 m, Austria<br>PROJ string:<br>Error when exporting to PROJ string: Unimplemented<br></div><div><br></div><div>WKT2:2019 string:<br>COORDINATEOPERATION[".... long WKT here...."]</div><div><br></div><div>What that PROJ Error means? Will it not be able to do the transform?<br></div><div><br></div><div>Then, I tried combining 2DCRS + VerticalCRS:</div><div><br></div><div>projinfo -s "EPSG:31255+5778" -t "EPSG:3035+9274"</div><div><br></div><div>And I get again 2 candidate operations and long PROJ and WKT Strings.</div><div>Now, when I try cs2cs to transform a coordinate I'm getting this:</div><div><br></div><div>cs2cs "EPSG:31255+5778" "EPSG:3035+9274"</div><div>88000 273000 600</div><div>Results into:</div><div>* * inf</div><div><br></div><div>Not really sure what it means. :-(</div><div>If I try a different vertical CRS</div><div><br></div><div><div>cs2cs "EPSG:31255+5778" "EPSG:3035+5621"</div><div>88000 273000 600</div><div>Results into:</div><div>2553923.81 4852657.42 600.00</div><div><br></div><div>So, at least the 2D coordinates get properly transformed but the elevation seems unchanged, therefore I'm not sure how it works.</div><div><br></div><div>Setting PROJ_DEBUG=2 I see this message running the above cs2cs command:</div><div><font size="1"><i>pj_open_lib(at_bev_AT_GIS_GRID.tif): call fopen(/opt/conda/pkgs/proj-data-1.0-1/share/proj/at_bev_AT_GIS_GRID.tif) - succeeded<br>pj_open_lib(GV_HoehenGrid_V1.csv): call fopen(/opt/conda/pkgs/proj-data-1.0-1/share/proj/GV_HoehenGrid_V1.csv) - succeeded<br>pj_open_lib(GV_Hoehengrid_plus_Geoid_V3.csv): call fopen(/opt/conda/pkgs/proj-data-1.0-1/share/proj/GV_Hoehengrid_plus_Geoid_V3.csv) - succeeded<br>Unrecognized vertical grid format<br>vgridshift: could not find required grid(s).<br>Pipeline: Bad step definition: inv (failed to load datum shift file)</i></font><br></div><div><br></div><div>That being said, I git cloned the PROJ repo and I have a couple of questions:</div><div>- how the vertical shift get actually computed when grid shift files are available?</div><div>I
mean, I suppose that when finding a grid_transformation entry in the
EPSG DB and looking for the vertical_offset_file associated to a file,
it will somehow load that file and use it for a kind of
interpolation/pixel query but I didn't figure out where this happens in
the code (checking a bit the vgridshift.cpp as well as
coordinateoperation.cpp).</div><div><br></div><div>- Does it support at the same time csv / tiffs / gtx? (If so, I didn't manage to find where it eventually loads them)</div><div><br></div><div>Thanks for your feedbacks in advance and sorry if any of my question doesn't make sense. <br></div><div><br></div><div>Best Regards,</div><div>Daniele</div></div><br clear="all"><br>-- <br><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><div><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr">Regards,</div><div dir="ltr">Daniele Romagnoli</div><div dir="ltr">==</div><div dir="ltr">GeoServer Professional Services from the experts! Visit <a href="http://goo.gl/it488V" target="_blank">http://goo.gl/it488V</a> for more information.</div><div dir="ltr">==</div><div dir="ltr"><br></div><div dir="ltr">Ing. Daniele Romagnoli</div><div dir="ltr">Senior Software Engineer</div><div dir="ltr"><br></div><div dir="ltr">GeoSolutions S.A.S.</div><div dir="ltr">Via di Montramito 3/A</div><div dir="ltr">55054 Massarosa (LU)</div><div dir="ltr">Italy</div><div dir="ltr">phone: +39 0584 962313</div><div dir="ltr">fax: +39 0584 1660272</div><div dir="ltr"><br></div><div dir="ltr"><a href="http://www.geo-solutions.it" target="_blank">http://www.geo-solutions.it</a></div><div dir="ltr"><a href="http://twitter.com/geosolutions_it" target="_blank">http://twitter.com/geosolutions_it</a></div><div dir="ltr"><br></div><div dir="ltr"><div dir="ltr"><span style="font-size:12.8px">-------------------------------------------------------</span></div><div dir="ltr"><span style="font-size:12.8px"><br></span></div><div dir="ltr"><span style="font-size:12.8px">Con riferimento alla normativa sul trattamento dei dati personali (Reg. UE 2016/679 - Regolamento generale sulla protezione dei dati “GDPR”), si precisa che ogni circostanza inerente alla presente email (il suo contenuto, gli eventuali allegati, etc.) è un dato la cui conoscenza è riservata al/i solo/i destinatario/i indicati dallo scrivente. Se il messaggio Le è giunto per errore, è tenuta/o a cancellarlo, ogni altra operazione è illecita. Le sarei comunque grato se potesse darmene notizia.</span></div><div dir="ltr"><span style="font-size:12.8px"><br></span></div><div dir="ltr"><span style="font-size:12.8px">This email is intended only for the person or entity to which it is addressed and may contain information that is privileged, confidential or otherwise protected from disclosure. We remind that - as provided by European Regulation 2016/679 “GDPR” - copying, dissemination or use of this e-mail or the information herein by anyone other than the intended recipient is prohibited. If you have received this email by mistake, please notify us immediately by telephone or e-mail.</span></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>