On lundi 18 mai 2020 11:17:52 CEST Rahkonen Jukka (MML) wrote: > Hi, > > This command > ogr2ogr -f "MapInfo file" -s_srs epsg:3067 -t_srs epsg:2393 2393.mif > tm35.jml writes into MIF > CoordSys Earth Projection 8, 104, "m", 27, 0, 1, 3500000, 0 > > ogrinfo shows > > ogrinfo 2393.mif -al -so > INFO: Open of `2393.mif' > using driver `MapInfo File' successful. > > Layer name: 2393 > Geometry: Unknown (any) > Feature Count: 3 > Extent: (3284260.027390, 6962722.914217) - (3284610.369420, 6962941.953889) > Layer SRS WKT: > PROJCRS["unnamed", > BASEGEOGCRS["unnamed", > DATUM["World Geodetic System 1984", > ELLIPSOID["WGS 84",6378137,298.257223563, > LENGTHUNIT["metre",1, > ID["EPSG",9001]]]], > PRIMEM["Greenwich",0, > ANGLEUNIT["degree",0.0174532925199433, > ID["EPSG",9122]]]], > CONVERSION["unnamed", > METHOD["Transverse Mercator", > ID["EPSG",9807]], > PARAMETER["Latitude of natural origin",0, > ANGLEUNIT["degree",0.0174532925199433], > ID["EPSG",8801]], > PARAMETER["Longitude of natural origin",27, > ANGLEUNIT["degree",0.0174532925199433], > ID["EPSG",8802]], > PARAMETER["Scale factor at natural origin",1, > SCALEUNIT["unity",1], > ID["EPSG",8805]], > PARAMETER["False easting",3500000, > LENGTHUNIT["metre",1], > ID["EPSG",8806]], > PARAMETER["False northing",0, > LENGTHUNIT["metre",1], > ID["EPSG",8807]]], > CS[Cartesian,2], > AXIS["easting",east, > ORDER[1], > LENGTHUNIT["metre",1, > ID["EPSG",9001]]], > AXIS["northing",north, > ORDER[2], > LENGTHUNIT["metre",1, > ID["EPSG",9001]]]] > Data axis to CRS axis mapping: 1,2 > > When I convert this data back into EPSG:3067 the coordinates are shifted by > a hundred meters probably because what was called towgs84 parameters are > not applied. Parameters appear in the mitab source code > https://github.com/OSGeo/gdal/blob/master/gdal/ogr/ogrsf_frmts/mitab/mitab_ > spatialref.cpp#L251 { 0, 1016,"Finnish_KKJ", 4, -96.062, > -82.428, -121.754, -4.801, -0.345, 1.376, 1.496, 0}, > > I tried to fix the MIF by changing the CoordSys line into > CoordSys Earth Projection 24, 1016, "m", 27, 0, 1, 3500000, 0 > that is to my knowledge what MapInfo itself is using but that does not work > at all with GDAL > > ogr2ogr -f "jml" -t_srs epsg:3067 2393_alt_from_mif.jml 2393_alt.mif > ERROR 1: PROJ: proj_as_proj_string: Unsupported conversion method: > Transverse_Mercator_MapInfo_24 ERROR 6: Cannot find coordinate operations > from > `PROJCRS["unnamed",BASEGEOGCRS["unnamed",DATUM["Finnish_KKJ",ELLIPSOID["Int > ernational > 1924",6378388,297,LENGTHUNIT["metre",1,ID["EPSG",9001]]]],PRIMEM["Greenwich > ",0,ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9122]]]],CONVERSION["unn > amed",METHOD["Transverse_Mercator_MapInfo_24"],PARAMETER["latitude_of_origin > ",0,ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9122]]],PARAMETER["centr > al_meridian",27,ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9122]]],PARA > METER["scale_factor",1,SCALEUNIT["unity",1,ID["EPSG",9201]]],PARAMETER["fals > e_easting",3500000,LENGTHUNIT["metre",1,ID["EPSG",9001]]],PARAMETER["false_n > orthing",0,LENGTHUNIT["metre",1,ID["EPSG",9001]]]],CS[Cartesian,2],AXIS["eas > ting",east,ORDER[1],LENGTHUNIT["metre",1,ID["EPSG",9001]]],AXIS["northing",n > orth,ORDER[2],LENGTHUNIT["metre",1,ID["EPSG",9001]]]]' to `EPSG:3067' ERROR > 1: Failed to create coordinate transformation between the > following coordinate systems. This may be because they > are not transformable. > > Is there something that I could do for making the conversion to round-trip?
Temptative fix for both datum and projection code in https://github.com/OSGeo/gdal/pull/2577 I presume the separate codes for the TMerc projection on KKJ and the regular one came from using the Snyder's tmerc formula vs using the extended one. Even -- Spatialys - Geospatial professional services http://www.spatialys.com
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