[GRASS-user] Datum not recognized by Grass

Markus Metz markus.metz.giswork at gmail.com
Tue Dec 3 12:56:39 PST 2019


There are some solutions to the problem of datum
<Qatar_National_Datum_1995> not recognized by GRASS:

- add Qatar_National_Datum_1995 to the datums known by GRASS
- 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

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.

Markus M

On Tue, Dec 3, 2019 at 8:52 PM Helmut Kudrnovsky <hellik at web.de> wrote:

> Markus Neteler wrote
> > Hi,
> >
> > On Mon, Dec 2, 2019 at 9:49 AM Zoltan Szecsei <
>
> > zoltans at .co
>
> > > wrote:
> >>
> >> Hi,
> >> I'm using EPSG 2932 and QGIS etc all are OK with it.
> >>
> >> I have installed everything using OSGeo4W64, so how come Grass does not
> >> use the same projections database (as QGis etc)?
> >> (and please can I have a pointer as to how to introduce EPSG 2932 to
> >> Grass 7.8.1)
> >>
> >> Thanks and regards,
> >> Zoltan
> >>
> >> ******** Running against:
> >> D:\GDBroad_tiles\shp_road_poly_few\23103770_road_poly.shp
> >> WARNING: Datum
> > <Qatar_National_Datum_1995>
> >  not recognised by GRASS and
> >> no parameters found
> >
> > Is it possible that you have a PROJ software version mixup?
> >
> > I tried on my Linux box:
> >
> > grass78 -c epsg:2932 ~/grassdata/test_2932
> > Starting GRASS GIS...
> > Creating new GRASS GIS location
> > <test_2932>
> > ...
> > Cleaning up temporary files...
> >
> >           __________  ___   __________    _______________
> >          / ____/ __ \/   | / ___/ ___/   / ____/  _/ ___/
> >         / / __/ /_/ / /| | \__ \\_  \   / / __ / / \__ \
> >        / /_/ / _, _/ ___ |___/ /__/ /  / /_/ // / ___/ /
> >        \____/_/ |_/_/  |_/____/____/   \____/___//____/
> >
> > Welcome to GRASS GIS 7.8.2dev (ad4836c73)
> > ...
> >
> > GRASS 7.8.2dev (test_2932):~ > g.proj -w
> > PROJCS["QND95 / Qatar National Grid",
> >     GEOGCS["QND95",
> >         DATUM["Qatar_National_Datum_1995",
> >             SPHEROID["International 1924",6378388,297,
> >                 AUTHORITY["EPSG","7022"]],
> >
> >
> TOWGS84[-119.4248,-303.65872,-11.00061,1.164298,0.174458,1.096259,3.657065],
> >             AUTHORITY["EPSG","6614"]],
> >         PRIMEM["Greenwich",0,
> >             AUTHORITY["EPSG","8901"]],
> >         UNIT["degree",0.0174532925199433,
> >             AUTHORITY["EPSG","9122"]],
> >         AUTHORITY["EPSG","4614"]],
> >     PROJECTION["Transverse_Mercator"],
> >     PARAMETER["latitude_of_origin",24.45],
> >     PARAMETER["central_meridian",51.21666666666667],
> >     PARAMETER["scale_factor",0.99999],
> >     PARAMETER["false_easting",200000],
> >     PARAMETER["false_northing",300000],
> >     UNIT["metre",1,
> >         AUTHORITY["EPSG","9001"]],
> >     AXIS["Easting",EAST],
> >     AXIS["Northing",NORTH],
> >     AUTHORITY["EPSG","2932"]]
>
> when importing a shapefile with the same epsg projection, I get:
>
> v.in.ogr --verbose input=D:\wd\test_epsg2932.shp
>
> Using OGR driver 'ESRI Shapefile/ESRI Shapefile'
> WARNING: Datum <Qatar_National_Datum_1995> von GRASS nicht erkannt und
> keine
> Parameter gefunden.
> Die Projektionsinformationen des Eingabedatensatzes und der aktuellen
> Location scheinen ├╝bereinzustimmen.
>
> D:\wd>ogrinfo --version
> GDAL 3.0.2, released 2019/10/28
>
> D:\wd>ogrinfo test_epsg2932.shp -al -so
> INFO: Open of `test_epsg2932.shp'
>       using driver `ESRI Shapefile' successful.
>
> Layer name: test_epsg2932
> Metadata:
>   DBF_DATE_LAST_UPDATE=2019-12-03
> Geometry: Point
> Feature Count: 1
> Extent: (823205.438352, 25769.568359) - (823205.438352, 25769.568359)
> Layer SRS WKT:
> PROJCS["QND95 / Qatar National Grid",
>     GEOGCS["QND95",
>         DATUM["Qatar_National_Datum_1995",
>             SPHEROID["International 1924",6378388,297,
>                 AUTHORITY["EPSG","7022"]],
>             AUTHORITY["EPSG","6614"]],
>         PRIMEM["Greenwich",0,
>             AUTHORITY["EPSG","8901"]],
>         UNIT["degree",0.0174532925199433,
>             AUTHORITY["EPSG","9122"]],
>         AUTHORITY["EPSG","4614"]],
>     PROJECTION["Transverse_Mercator"],
>     PARAMETER["latitude_of_origin",24.45],
>     PARAMETER["central_meridian",51.2166666666667],
>     PARAMETER["scale_factor",0.99999],
>     PARAMETER["false_easting",200000],
>     PARAMETER["false_northing",300000],
>     UNIT["metre",1,
>         AUTHORITY["EPSG","9001"]],
>     AXIS["Easting",EAST],
>     AXIS["Northing",NORTH],
>     AUTHORITY["EPSG","2932"]]
> Data axis to CRS axis mapping: 1,2
> id: Integer64 (10.0)
> test: Integer (9.0)
>
> D:\wd>testepsg test_epsg2932.prj
> Validate Succeeds.
> WKT[test_epsg2932.prj] =
> PROJCS["QND95 / Qatar National Grid",
>     GEOGCS["QND95",
>         DATUM["Qatar_National_Datum_1995",
>             SPHEROID["International 1924",6378388,297,
>                 AUTHORITY["EPSG","7022"]],
>             AUTHORITY["EPSG","6614"]],
>         PRIMEM["Greenwich",0],
>         UNIT["Degree",0.0174532925199433]],
>     PROJECTION["Transverse_Mercator"],
>     PARAMETER["latitude_of_origin",24.45],
>     PARAMETER["central_meridian",51.2166666666667],
>     PARAMETER["scale_factor",0.99999],
>     PARAMETER["false_easting",200000],
>     PARAMETER["false_northing",300000],
>     UNIT["metre",1,
>         AUTHORITY["EPSG","9001"]],
>     AXIS["Easting",EAST],
>     AXIS["Northing",NORTH]]
>
> Simplified WKT[test_epsg2932.prj] =
> PROJCS["QND95 / Qatar National Grid",
>     GEOGCS["QND95",
>         DATUM["Qatar_National_Datum_1995",
>             SPHEROID["International 1924",6378388,297]],
>         PRIMEM["Greenwich",0],
>         UNIT["Degree",0.0174532925199433]],
>     PROJECTION["Transverse_Mercator"],
>     PARAMETER["latitude_of_origin",24.45],
>     PARAMETER["central_meridian",51.2166666666667],
>     PARAMETER["scale_factor",0.99999],
>     PARAMETER["false_easting",200000],
>     PARAMETER["false_northing",300000],
>     UNIT["metre",1]]
>
> Old Style WKT[test_epsg2932.prj] = PROJCS["QND95 / Qatar National
>
> Grid",GEOGCS["QND95",DATUM["Qatar_National_Datum_1995",SPHEROID["International
>
> 1924",6378388,297]],PRIMEM["Greenwich",0],UNIT["Degree",0.0174532925199433]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",24.45],PARAMETER["central_meridian",51.2166666666667],PARAMETER["scale_factor",0.99999],PARAMETER["false_easting",200000],PARAMETER["false_northing",300000],UNIT["metre",1]]
> ESRI'ified WKT[test_epsg2932.prj] =
> PROJCS["QND_1995_Qatar_National_Grid",
>     GEOGCS["GCS_QND_1995",
>         DATUM["D_QND_1995",
>             SPHEROID["International_1924",6378388.0,297.0]],
>         PRIMEM["Greenwich",0.0],
>         UNIT["Degree",0.0174532925199433]],
>     PROJECTION["Transverse_Mercator"],
>     PARAMETER["False_Easting",200000.0],
>     PARAMETER["False_Northing",300000.0],
>     PARAMETER["Central_Meridian",51.2166666666667],
>     PARAMETER["Scale_Factor",0.99999],
>     PARAMETER["Latitude_Of_Origin",24.45],
>     UNIT["Meter",1.0]]
> PROJ.4 rendering of [test_epsg2932.prj] = +proj=tmerc +lat_0=24.45
> +lon_0=51.2166666666667 +k=0.99999 +x_0=200000 +y_0=300000 +ellps=intl
> +units=m +no_defs
>
> maybe worth to open a ticket
>
>
>
>
> -----
> best regards
> Helmut
> --
> Sent from: http://osgeo-org.1560.x6.nabble.com/Grass-Users-f3884509.html
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