Hi, Sorry for taking the time to get back to you.
We tested and it doesn't work. We still have the offset on the coordinates. I think the problem is with this file: https://github.com/OSGeo/proj-datumgrid/blob/master/ntf_r93.gsb in the project folder, the file that we have is probably not the best one. To install the file again, is there a projection package? Before we had a projection package with this file: dnf install *proj*, does this still exist? Thank you for your help. Best, Rhea > On 5 Sep 2023, at 12:51 PM, Even Rouault <[email protected]> wrote: > > Hi, > > The WKT1 string for your IGNF:LAMB1 contains latitude_of_origin = 49.5. But > this is wrong. This is the value in degree, but it should be expressed in > grads as the GEOGCS unit is grad (cf > https://gdal.org/tutorials/wktproblems.html#units-of-parameters), so 55 grad > > The correct WKT definition to use is: > > PROJCS["NTF Lambert I", > GEOGCS["NTF geographiques Paris (gr)", > DATUM["Nouvelle_Triangulation_Francaise_Paris", > SPHEROID["Clarke 1880 (IGN)",6378249.2,293.466021293627, > AUTHORITY["EPSG","7011"]], > AUTHORITY["EPSG","6807"]], > PRIMEM["Paris",2.33722917, > AUTHORITY["EPSG","8903"]], > UNIT["grad",0.0157079632679489, > AUTHORITY["EPSG","9105"]], > AUTHORITY["IGNF","NTFPGRAD"]], > PROJECTION["Lambert_Conformal_Conic_1SP"], > PARAMETER["latitude_of_origin",55], > PARAMETER["central_meridian",0], > PARAMETER["scale_factor",0.99987734], > PARAMETER["false_easting",600000], > PARAMETER["false_northing",200000], > UNIT["metre",1, > AUTHORITY["EPSG","9001"]], > AXIS["Easting",EAST], > AXIS["Northing",NORTH], > AUTHORITY["IGNF","LAMB1"]] > > With recent PROJ, I get the correct value when using the proj.4 string or the > corrected WKT1 definition (got from "projinfo IGNF:LAMB1 -o WKT1:GDAL") > > $ echo 398845.80866241 6822815.8927889 | PROJ_DATA=data PROJ_NETWORK=ON > bin/cs2cs EPSG:2154 +to +proj=lcc +nadgrids=ntf_r93.gsb,null +a=6378249.2000 > +rf=293.4660210000000 +pm=2.337229167 +lat_0=49.500000000 +lon_0=0.000000000 > +k_0=0.99987734 +lat_1=49.500000000 +x_0=600000.000 +y_0=200000.000 +units=m > +no_defs > 347762.11 87364.03 0.00 > > $ echo 398845.80866241 6822815.8927889 | PROJ_DATA=data PROJ_NETWORK=ON > bin/cs2cs EPSG:2154 'PROJCS["NTF Lambert I",GEOGCS["NTF geographiques Paris > (gr)",DATUM["Nouvelle_Triangulation_Francaise_Paris",SPHEROID["Clarke 1880 > (IGN)",6378249.2,293.466021293627,AUTHORITY["EPSG","7011"]],AUTHORITY["EPSG","6807"]],PRIMEM["Paris",2.33722917,AUTHORITY["EPSG","8903"]],UNIT["grad",0.0157079632679489,AUTHORITY["EPSG","9105"]],AUTHORITY["IGNF","NTFPGRAD"]],PROJECTION["Lambert_Conformal_Conic_1SP"],PARAMETER["latitude_of_origin",55],PARAMETER["central_meridian",0],PARAMETER["scale_factor",0.99987734],PARAMETER["false_easting",600000],PARAMETER["false_northing",200000],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["IGNF","LAMB1"]]' > 347762.11 87364.03 0.00 > > Even > > Le 05/09/2023 à 12:19, Rhea a écrit : >> hello, >> >> I am using this definition for my projection on both postgis 2 and postgis 3 >> so i can use it in my st_transform() function: >> >> INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext) >> values ( 932001, 'IGNF' , 320002101 , '+proj=lcc +nadgrids=ntf_r93.gsb,null >> +a=6378249.2000 +rf=293.4660210000000 +pm=2.337229167 +lat_0=49.500000000 >> +lon_0=0.000000000 +k_0=0.99987734 +lat_1=49.500000000 +x_0=600000.000 >> +y_0=200000.000 +units=m +no_defs' , 'PROJCS["Lambert I",GEOGCS["Nouvelle >> Triangulation Française Paris grades",DATUM["NTF",SPHEROID["Clarke 1880 >> IGN",6378249.2000,293.4660210000000,AUTHORITY["IGNF","ELG010"]],TOWGS84[-168.0000,-60.0000,320.0000,0,0,0,0],AUTHORITY["IGNF","REG002"]],PRIMEM["Paris",2.337229167,AUTHORITY["IGNF","LGO02"]],UNIT["grad",0.01570796326794897],AXIS["Longitude",EAST],AXIS["Latitude",NORTH],AUTHORITY["IGNF","NTFP"]],PROJECTION["Lambert_Conformal_Conic_1SP",AUTHORITY["IGNF","PRC0101"]],PARAMETER["semi_major",6378249.2000],PARAMETER["semi_minor",6356515.0000],PARAMETER["latitude_of_origin",49.500000000],PARAMETER["central_meridian",0.000000000],PARAMETER["scale_factor",0.99987734],PARAMETER["false_easting",600000.000],PARAMETER["false_northing",200000.000],UNIT["metre",1],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["IGNF","LAMB1"]]’); >> This projection 932001 corresponds to Lambert Zone 1 corrected with the IGN >> grid. >> This is the function where im using this projection : >> >> select st_astext(st_transform(st_setsrid(st_point(398845.80866241, >> 6822815.8927889), 2154), 932001)) >> On our PostgreSQL 10 / PostGIS 2.x machine, i am getting this: >> >> POINT(347762.11171084 87364.0318659853) >> While in PostgresQL 13 / PostGIS 3.x, i am getting this (result which is >> incorrect): >> >> POINT(347200.5307476731 637506.2948565462) >> Result of the query select postgis_full_version(); on our 2 environments: >> PostgreSQL 10 : POSTGIS="2.4.7 r17330" PGSQL="100" GEOS="3.7.1-CAPI-1.11.1 >> 27a5e771" PROJ="Rel. 4.9.3, 15 August 2016" GDAL="GDAL 2.3.2, released >> 2018/09/21" LIBXML="2.9.1" LIBJSON="0.11" RASTER >> >> >> PostgresSQL 13 : POSTGIS="3.1.8 c5ebc1f" [EXTENSION] PGSQL="130" >> GEOS="3.10.3-CAPI-1.16.1" PROJ="8.2.1" LIBXML="2.9.7" LIBJSON="0.13.1" >> LIBPROTOBUF="1.3.0" WAGYU="0.5.0 (Internal)” TOPOLOGY >> I tried using fr_ign_ntf_r93.tif instead of the ntf_r93.gsb but it didnt >> work, i got the same results. >> I tried verifying that the ntf_r93.gsb or the fr_ign_ntf_r93.tif are >> located in usr/share/proj/ directory and they do but yet im getting the same >> results. >> can anyone help me please? >> Thank you so much ! >> >> >> >> >> _______________________________________________ >> PROJ mailing list >> [email protected] <mailto:[email protected]> >> https://lists.osgeo.org/mailman/listinfo/proj > -- > http://www.spatialys.com <http://www.spatialys.com/> > My software is free, but my time generally not.
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