Re: [Qgis-user] ITRF00
On vendredi 13 décembre 2019 13:01:36 CET malcolm wrote: > The proj definition below is what I am using to convert data using PostGIS > from NAD83 to WGS84 in a separate application. This creates data that > matches what is transformed from ArcMap using the ITRF00 transformation > (which is default in the latest version). The NAD83 datum in PostGIS is > simply towgs84=0,0,0,0,0,0,0. I am using the 3735 projection for NAD83 > (Ohio SP South). > > +proj=lcc +lat_1=40.03 +lat_2=38.73 +lat_0=38 > +lon_0=-82.5 +x_0=60 +y_0=0 +ellps=GRS80 > +towgs84=-0.9956,1.9013,0.5215,0.025915,0.009246,0.011599,-0.00062 > +units=us-ft +no_defs > (adding back the list) OK, so from the above parameters and digging into the EPSG database, it seems to be the NAD83(CORS96) to ITRF2000 transformation, with the omission of the time dependant terms: $ projinfo -s "NAD83(CORS96)" -t ITRF2000 --spatial-test intersects -o PROJ Candidate operations found: 2 - Operation n°1: unknown id, Conversion from NAD83(CORS96) (geog2D) to NAD83(CORS96) (geocentric) + Inverse of ITRF2000 to NAD83(CORS96) (1) + Conversion from ITRF2000 (geocentric) to ITRF2000 (geog2D), 0 m, USA - CONUS and Alaska; PRVI PROJ string: +proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +proj=cart +ellps=GRS80 +step +inv +proj=helmert +x=0.9956 +y=-1.9013 +z=-0.5215 +rx=0.025915 +ry=0.009426 +rz=0.011599 +s=0.00062 +dx=0.0007 +dy=-0.0007 +dz=0.0005 +drx=6.7e-05 +dry=-0.000757 +drz=-5.1e-05 +ds=-0.00018 +t_epoch=1997 +convention=coordinate_frame +step +inv +proj=cart +ellps=GRS80 +step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1 -- Spatialys - Geospatial professional services http://www.spatialys.com ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] ITRF00
On vendredi 13 décembre 2019 12:00:23 CET malcolm wrote: > Question on how QGIS chooses its transformations. I am assuming it is from > some proj defaults?? I want to know because I do not see the current > NAD83<>WGS84 transformation (ITRF00) which is used by HAZUS and Esri. Is > there any way to add this upstream so it is used if not by default at least > as an option in QGIS? Which transformations do they use ? I can get non-null transformations with PROJ if using NAD83(2011) as source CRS and ITRF2000 as target: They go through ITRF2008 or ITRF2014 as intermediate. However as those are time-dependent transformations, you'd need to specify a coordinate epoch to get very accurate results, which is not (yet?) possible through QGIS AFAIK. $ projinfo -s "NAD83(2011)" -t ITRF2000 --spatial-test intersects -o PROJ Candidate operations found: 2 - Operation n°1: unknown id, Conversion from NAD83(2011) (geog2D) to NAD83(2011) (geocentric) + Inverse of ITRF2008 to NAD83(2011) (1) + Inverse of ITRF2000 to ITRF2008 (1) + Conversion from ITRF2000 (geocentric) to ITRF2000 (geog2D), 0.01 m, USA - CONUS and Alaska; PRVI PROJ string: +proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +proj=cart +ellps=GRS80 +step +inv +proj=helmert +x=0.99343 +y=-1.90331 +z=-0.52655 +rx=0.02591467 +ry=0.00942645 +rz=0.01159935 +s=0.00171504 +dx=0.00079 +dy=-0.0006 +dz=-0.00134 +drx=6.667e-05 +dry=-0.00075744 +drz=-5.133e-05 +ds=-0.00010201 +t_epoch=1997 +convention=coordinate_frame +step +inv +proj=helmert +x=0.0019 +y=0.0017 +z=0.0105 +rx=0 +ry=0 +rz=0 +s=-0.00134 +dx=-0.0001 +dy=-0.0001 +dz=0.0018 +drx=0 +dry=0 +drz=0 +ds=-8e-05 +t_epoch=2000 +convention=position_vector +step +inv +proj=cart +ellps=GRS80 +step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1 - Operation n°2: unknown id, Conversion from NAD83(2011) (geog2D) to NAD83(2011) (geocentric) + Inverse of ITRF2014 to NAD83(2011) (1) + Inverse of ITRF2000 to ITRF2014 (1) + Conversion from ITRF2000 (geocentric) to ITRF2000 (geog2D), 0.01 m, USA - CONUS and Alaska; PRVI PROJ string: +proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +proj=cart +ellps=GRS80 +step +inv +proj=helmert +x=1.0053 +y=-1.9092 +z=-0.5416 +rx=0.0267814 +ry=-0.0004203 +rz=0.0109321 +s=0.00037 +dx=0.0008 +dy=-0.0006 +dz=-0.0014 +drx=6.67e-05 +dry=-0.0007574 +drz=-5.13e-05 +ds=-7.01e-05 +t_epoch=2010 +convention=coordinate_frame +step +inv +proj=helmert +x=-0.0007 +y=-0.0012 +z=0.0261 +rx=0 +ry=0 +rz=0 +s=-0.00212 +dx=-0.0001 +dy=-0.0001 +dz=0.0019 +drx=0 +dry=0 +drz=0 +ds=-0.00011 +t_epoch=2010 +convention=position_vector +step +inv +proj=cart +ellps=GRS80 +step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1 Even -- Spatialys - Geospatial professional services http://www.spatialys.com ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
[Qgis-user] ITRF00
Question on how QGIS chooses its transformations. I am assuming it is from some proj defaults?? I want to know because I do not see the current NAD83<>WGS84 transformation (ITRF00) which is used by HAZUS and Esri. Is there any way to add this upstream so it is used if not by default at least as an option in QGIS? Thanks ___ Qgis-user mailing list Qgis-user@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-user Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
