[GRASS-user] Datum not recognized by Grass

[Helmut Kudrnovsky]

> ignore the warning and use GRASS with PROJ6, granted that authority name
(e.g. EPSG) and authority code (e.g. 2932) are known for both CRS's in case
of reprojection

this issue is already by GRASS with PROJ6, see

####################
GRASS version: 7.8.1                                                            
Code revision: c865432c9                                                        
Build date: 2019-11-10                                                          
Build platform: x86_64-w64-mingw32                                              
GDAL: 3.0.2                                                                     
PROJ: 6.2.1  <=                                                              
GEOS: 3.8.0                                                                     
SQLite: 3.29.0                                                                  
Python: 3.7.0                                                                   
wxPython: 4.0.7                                                                 
Platform: Windows-10-10.0.18362-SP0 (OSGeo4W)  
####################

and the output from the underlying PROJ: 6.2.1

####################
C:\>projinfo EPSG:2932 -o PROJ,WKT2_2018
PROJ.4 string:
+proj=tmerc +lat_0=24.45 +lon_0=51.2166666666667 +k=0.99999 +x_0=200000
+y_0=300000 +ellps=intl
+towgs84=-119.4248,-303.65872,-11.00061,1.164298,0.174458,1.096259,3.657065
+units=m +no_defs +type=crs

WKT2_2018 string:
PROJCRS["QND95 / Qatar National Grid",
    BASEGEOGCRS["QND95",
        DATUM["Qatar National Datum 1995",
            ELLIPSOID["International 1924",6378388,297,
                LENGTHUNIT["metre",1]]],
        PRIMEM["Greenwich",0,
            ANGLEUNIT["degree",0.0174532925199433]],
        ID["EPSG",4614]],
    CONVERSION["Qatar National Grid",
        METHOD["Transverse Mercator",
            ID["EPSG",9807]],
        PARAMETER["Latitude of natural origin",24.45,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8801]],
        PARAMETER["Longitude of natural origin",51.2166666666667,
            ANGLEUNIT["degree",0.0174532925199433],
            ID["EPSG",8802]],
        PARAMETER["Scale factor at natural origin",0.99999,
            SCALEUNIT["unity",1],
            ID["EPSG",8805]],
        PARAMETER["False easting",200000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8806]],
        PARAMETER["False northing",300000,
            LENGTHUNIT["metre",1],
            ID["EPSG",8807]]],
    CS[Cartesian,2],
        AXIS["(E)",east,
            ORDER[1],
            LENGTHUNIT["metre",1]],
        AXIS["(N)",north,
            ORDER[2],
            LENGTHUNIT["metre",1]],
    USAGE[
        SCOPE["unknown"],
        AREA["Qatar - onshore"],
        BBOX[24.55,50.69,26.2,51.68]],
    ID["EPSG",2932]]
####################

>The problem is that GRASS still assumes datum transformation from X to
WGS84, whereas with PROJ6, 
>WGS84 is no longer required as pivot datum. Datum transformations from
datum X to datum Y can 
>sometimes (often) be done without going through WGS84. The requirement is
to have EPSG or other 
>authority codes and to use PROJ 6.

this warning is just from a simple v.in.ogr of a EPSG:2932-based shapefile
into a EPSG:2932-created GRASS location.

so, there may be some more adaptions needed for actions like v.in.ogr and
co?



-----
best regards
Helmut
--
Sent from: http://osgeo-org.1560.x6.nabble.com/Grass-Users-f3884509.html