I want to convert or reproject in the fly some shape files and raster between between different datums using custom transformation parameters (7 parameters) but don't know how to do that in QGIS.
I want to know the string of the final transformation, transformation matrice of rotation (my parameters are in seconds and scale is in ppm) that QGIS uses and if that string works only in one direction of the transformation or it automatically calculate the reverse transformation too?
In my scenario i want to go through this:
Epsg:3127 to Epsg:32634 (Transf. parameters are tx=0.0527 m ty=0.0509 m tz=-0.06636 m rx=-0.001456" ry=-0.008809" rz=0.014238" scale=0.000958 ppm)
Epsg:32634 to Epsg:28404 (Transf. parameters are tx=44.183 m ty=0.580 m tz=-38.489 m rx=2.3867" ry=2.7072" rz=-3.5196" scale=8.2703 ppm)
And how can i combine this 2 transformation paths in one so i can go directly from Epsg:3127 to Epsg:28404 and vice versa.
Here is the .gtf (32634 to 2642) contents created from the tool "create custom geographic transformation"
1DøÁÒ½ øu¼Î ] GEOGTRAN["H_TRANS",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],GEOGCS["GCS_Pulkovo_1942",DATUM["D_Pulkovo_1942",SPHEROID["Krasovsky_1940",6378245.0,298.3]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],METHOD["Coordinate_Frame"],PARAMETER["X_Axis_Translation",44.183],PARAMETER["Y_Axis_Translation",0.58],PARAMETER["Z_Axis_Translation",38.489],PARAMETER["X_Axis_Rotation",2.3867],PARAMETER["Y_Axis_Rotation",2.7072],PARAMETER["Z_Axis_Rotation",-3.5196],PARAMETER["Scale_Difference",8.2703]]
and here is the .gtf (32634 to 3127 or 6870) contents created from the tool "create custom geographic transformation"
1DøÁÒ½ øu¼Î u GEOGTRAN["UTM_KRGJSH_WGS_GK20FIN",GEOGCS["GCS_WGS_1984",DATUM["D_WGS_1984",SPHEROID["WGS_1984",6378137.0,298.257223563]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],GEOGCS["GCS_ETRS_1989",DATUM["D_ETRS_1989",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],METHOD["Coordinate_Frame"],PARAMETER["X_Axis_Translation",0.0527],PARAMETER["Y_Axis_Translation",0.0509],PARAMETER["Z_Axis_Translation",-0.06636],PARAMETER["X_Axis_Rotation",-0.001456],PARAMETER["Y_Axis_Rotation",-0.008809],PARAMETER["Z_Axis_Rotation",0.014238],PARAMETER["Scale_Difference",0.000958]]
EPSG:2462 Albanian 1987/GK zone 4
, but all values with reversed signs. – AndreJ Jun 27 '17 at 16:11