Question about Datum not recognised by GRASS

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Question about Datum not recognised by GRASS

Zac45
Hi,

I am quite new to GRASS and this is my first post, looking for some help
here!

I am now processing the dataset under *CGCS2000 / 3-degree Gauss-Kruger CM
120E*. But the dataset could not be recognised by GRASS when I trying to
import the DEM data.  The warning message kept poping up:

WARNING: Datum <China_2000> not recognised by GRASS and no parameters found

And the output from g.region -p is:

projection: 99 (CGCS2000 / 3-degree Gauss-Kruger CM 120E)
zone:       0
datum:      ** unknown (default: WGS84) **
ellipsoid:  grs80
north:      1
south:      0
west:       0
east:       1
nsres:      1
ewres:      1
rows:       1​
cols:       1
cells:      1

How can I fix it?

Best,
Zac45



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Re: Question about Datum not recognised by GRASS

Zac45
Sorry, the output of g.region -p is:
projection: 99 (CGCS2000 / 3-degree Gauss-Kruger CM 120E)
zone:       0
datum:      ** unknown (default: WGS84) **
ellipsoid:  grs80
north:      42.99666667
south:      41.54
west:       118.67083333
east:       121.465
nsres:      0.00083333
ewres:      0.00083333
rows:       1748
cols:       3353
cells:      5861044



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Re: Question about Datum not recognised by GRASS

Micha Silver-2
In reply to this post by Zac45

On 02/07/2020 20:58, Zac45 wrote:
Hi,

I am quite new to GRASS and this is my first post, looking for some help
here!
Welcome

I am now processing the dataset under *CGCS2000 / 3-degree Gauss-Kruger CM
120E*. But the dataset could not be recognised by GRASS when I trying to
import the DEM data.  The warning message kept poping up: 

Can you show the CRS of your original DEM before import into GRASS. What's the output from:


gdalinfo <your_original_DEM>

?



WARNING: Datum <China_2000> not recognised by GRASS and no parameters found

And the output from g.region -p is:

projection: 99 (CGCS2000 / 3-degree Gauss-Kruger CM 120E)
zone:       0
datum:      ** unknown (default: WGS84) **
ellipsoid:  grs80
north:      1
south:      0
west:       0
east:       1
nsres:      1
ewres:      1
rows:       1​
cols:       1
cells:      1

How can I fix it?

Best,
Zac45



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Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918
https://orcid.org/0000-0002-1128-1325

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Re: Question about Datum not recognised by GRASS

Micha Silver-2

On 03/07/2020 11:53, 李泽浩 wrote:
Hi Micha,

Thanks for your reply! Here is the output from gdalinfo
This DEM is projected from WGS84 to CGCS 2000 in ArcMap first and then imported in GRASS.

gdalinfo C:\Users\zhangtong\Desktop\Zehao_DEM.tif                              
Driver: GTiff/GeoTIFF
Files: C:\Users\zhangtong\Desktop\Zehao_DEM.tif
Size is 3353, 1748
Coordinate System is:
PROJCS["CGCS2000_3_Degree_GK_CM_120E",
    GEOGCS["GCS_China_Geodetic_Coordinate_System_2000",
        DATUM["China_2000",
            SPHEROID["CGCS2000",6378137,298.257222101]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["central_meridian",120],
    PARAMETER["scale_factor",1],
    PARAMETER["false_easting",500000],
    PARAMETER["false_northing",0],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
Origin = (118.670833333333334,42.996666666666670)
Pixel Size = (0.000833333333333,-0.000833333333333)
Metadata:
  AREA_OR_POINT=Area
  DataType=Generic
Image Structure Metadata:
  INTERLEAVE=BAND
Corner Coordinates:
Upper Left  ( 118.6708333,  42.9966667) (115d30'50.80"E,  0d 0' 1.40"N)
Lower Left  ( 118.6708333,  41.5400000) (115d30'50.80"E,  0d 0' 1.35"N)
Upper Right ( 121.4650000,  42.9966667) (115d30'50.89"E,  0d 0' 1.40"N)
Lower Right ( 121.4650000,  41.5400000) (115d30'50.89"E,  0d 0' 1.35"N)
Center      ( 120.0679167,  42.2683333) (115d30'50.84"E,  0d 0' 1.37"N)
Band 1 Block=128x128 Type=Int16, ColorInterp=Gray
  NoData Value=32767




OK, that looks good.

Now you can create a new LOCATION for your GRASS data using that DEM projection information as follows:
(I'll assume you want your GRASS database under: C:\Users\zhangtong\grassdata)


grass -c C:\Users\zhangtong\Desktop\Zehao_DEM.tif -e C:\Users\zhangtong\grassdata\CGCS2000\PERMANENT


THis command creates a new LOCATION based on the DEM coordinate system, then exits (-e option).

Now start GRASS in that new location and you should be able to import your DEM without problem:


grass C:\Users\zhangtong\grassdata\CGCS2000\PERMANENT


and then at the GRASS command prompt:

r.import C:\Users\zhangtong\Desktop\Zehao_DEM.tif output=zehao_dem

g.region -ap rast=zehao_dem





Zac

Micha Silver <[hidden email]> 于2020年7月3日周五 下午4:43写道:

On 02/07/2020 20:58, Zac45 wrote:
Hi,

I am quite new to GRASS and this is my first post, looking for some help
here!
Welcome
I am now processing the dataset under *CGCS2000 / 3-degree Gauss-Kruger CM
120E*. But the dataset could not be recognised by GRASS when I trying to
import the DEM data.  The warning message kept poping up: 

Can you show the CRS of your original DEM before import into GRASS. What's the output from:


gdalinfo <your_original_DEM>

?


WARNING: Datum <China_2000> not recognised by GRASS and no parameters found

And the output from g.region -p is:

projection: 99 (CGCS2000 / 3-degree Gauss-Kruger CM 120E)
zone:       0
datum:      ** unknown (default: WGS84) **
ellipsoid:  grs80
north:      1
south:      0
west:       0
east:       1
nsres:      1
ewres:      1
rows:       1​
cols:       1
cells:      1

How can I fix it?

Best,
Zac45



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_______________________________________________
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-- 
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918
https://orcid.org/0000-0002-1128-1325
-- 
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918
https://orcid.org/0000-0002-1128-1325

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Re: Question about Datum not recognised by GRASS

Micha Silver-2

On 03/07/2020 12:33, 李泽浩 wrote:
Thanks for your advice! But I fail to run the " grass -c " code in the GRASS console. Is it should be run elsewhere?


(Keeping the thread on the list)


Sorry, you need to run the grass -c command *outside of grass*, at the regular command prompt (OSGeo2W shell if you installed from OSGeo4W)



Micha Silver <[hidden email]> 于2020年7月3日周五 下午5:07写道:

On 03/07/2020 11:53, 李泽浩 wrote:
Hi Micha,

Thanks for your reply! Here is the output from gdalinfo
This DEM is projected from WGS84 to CGCS 2000 in ArcMap first and then imported in GRASS.

gdalinfo C:\Users\zhangtong\Desktop\Zehao_DEM.tif                              
Driver: GTiff/GeoTIFF
Files: C:\Users\zhangtong\Desktop\Zehao_DEM.tif
Size is 3353, 1748
Coordinate System is:
PROJCS["CGCS2000_3_Degree_GK_CM_120E",
    GEOGCS["GCS_China_Geodetic_Coordinate_System_2000",
        DATUM["China_2000",
            SPHEROID["CGCS2000",6378137,298.257222101]],
        PRIMEM["Greenwich",0],
        UNIT["degree",0.0174532925199433]],
    PROJECTION["Transverse_Mercator"],
    PARAMETER["latitude_of_origin",0],
    PARAMETER["central_meridian",120],
    PARAMETER["scale_factor",1],
    PARAMETER["false_easting",500000],
    PARAMETER["false_northing",0],
    UNIT["metre",1,
        AUTHORITY["EPSG","9001"]]]
Origin = (118.670833333333334,42.996666666666670)
Pixel Size = (0.000833333333333,-0.000833333333333)
Metadata:
  AREA_OR_POINT=Area
  DataType=Generic
Image Structure Metadata:
  INTERLEAVE=BAND
Corner Coordinates:
Upper Left  ( 118.6708333,  42.9966667) (115d30'50.80"E,  0d 0' 1.40"N)
Lower Left  ( 118.6708333,  41.5400000) (115d30'50.80"E,  0d 0' 1.35"N)
Upper Right ( 121.4650000,  42.9966667) (115d30'50.89"E,  0d 0' 1.40"N)
Lower Right ( 121.4650000,  41.5400000) (115d30'50.89"E,  0d 0' 1.35"N)
Center      ( 120.0679167,  42.2683333) (115d30'50.84"E,  0d 0' 1.37"N)
Band 1 Block=128x128 Type=Int16, ColorInterp=Gray
  NoData Value=32767




OK, that looks good.

Now you can create a new LOCATION for your GRASS data using that DEM projection information as follows:
(I'll assume you want your GRASS database under: C:\Users\zhangtong\grassdata)


grass -c C:\Users\zhangtong\Desktop\Zehao_DEM.tif -e C:\Users\zhangtong\grassdata\CGCS2000\PERMANENT


THis command creates a new LOCATION based on the DEM coordinate system, then exits (-e option).

Now start GRASS in that new location and you should be able to import your DEM without problem:


grass C:\Users\zhangtong\grassdata\CGCS2000\PERMANENT


and then at the GRASS command prompt:

r.import C:\Users\zhangtong\Desktop\Zehao_DEM.tif output=zehao_dem

g.region -ap rast=zehao_dem





Zac

Micha Silver <[hidden email]> 于2020年7月3日周五 下午4:43写道:

On 02/07/2020 20:58, Zac45 wrote:
Hi,

I am quite new to GRASS and this is my first post, looking for some help
here!
Welcome
I am now processing the dataset under *CGCS2000 / 3-degree Gauss-Kruger CM
120E*. But the dataset could not be recognised by GRASS when I trying to
import the DEM data.  The warning message kept poping up: 

Can you show the CRS of your original DEM before import into GRASS. What's the output from:


gdalinfo <your_original_DEM>

?


WARNING: Datum <China_2000> not recognised by GRASS and no parameters found

And the output from g.region -p is:

projection: 99 (CGCS2000 / 3-degree Gauss-Kruger CM 120E)
zone:       0
datum:      ** unknown (default: WGS84) **
ellipsoid:  grs80
north:      1
south:      0
west:       0
east:       1
nsres:      1
ewres:      1
rows:       1​
cols:       1
cells:      1

How can I fix it?

Best,
Zac45



--
Sent from: http://osgeo-org.1560.x6.nabble.com/Grass-Users-f3884509.html
_______________________________________________
grass-user mailing list
[hidden email]
https://lists.osgeo.org/mailman/listinfo/grass-user
-- 
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918
https://orcid.org/0000-0002-1128-1325
-- 
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918
https://orcid.org/0000-0002-1128-1325
-- 
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918
https://orcid.org/0000-0002-1128-1325

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grass-user mailing list
[hidden email]
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