1

I do have a raster which shows 13 rows and 16 columns when viewing it with Windows Viewer and also when using imread for loading it into python.

I want to work with my dataset in GRASS. My steps:

    r.import input=RGI60-11.00083.tif output=RGI60 --overwrite
    g.region --overwrite raster=RGI60

However, when I now look at the raster in the Map Display, the raster has 12 rows and 22 columns. It seems that every third column is repeated. I loaded the tiff file to ArcMap, and it displayed correctly. I therefore think I might be having a problem with my grass configuration, but I am unable to find any configuration variable that might be causing this.

Sample data can be downloaded from here:
https://www.research-collection.ethz.ch/handle/20.500.11850/315707
Folder to download: composite_thickness_RGI60-18.zip
And then the first image: RGI60-18.00001_thickness.tif

How could I fix this problem?

enter image description here

2

I downloaded a zipfile and checked one of the rasters with gdalinfo:

micha@RMS RGI60-18 $ gdalinfo RGI60-18.00001_thickness.tif 
Driver: GTiff/GeoTIFF
Files: RGI60-18.00001_thickness.tif
Size is 13, 13
Coordinate System is:
PROJCS["WGS 84 / UTM zone 60S",

The raster size is reported as 13x13 and the coordinate system is UTM60S, So I created a new GRASS location using the Geotiff as follows:

grass -c RGI60-18.00001_thickness.tif ./UTM60S/

The -c says "create a location based on the georeferenced file RGI60-18.00001.tif", and place the GRASS database and location in the ./UTM60S directory.

Now I imported the Geotiff and set the computation region to match:

r.in.gdal RGI60-18.00001_thickness.tif output=RGI6018
micha@RMS RGI60-18 $ g.region -ap rast=RGI6018
projection: 1 (UTM)
zone:       -60
datum:      wgs84
ellipsoid:  wgs84
north:      5651812.5
south:      5651487.5
west:       374637.5
east:       374962.5
nsres:      25
ewres:      25
rows:       13
cols:       13
cells:      169

Note the -a flag ("align") to g.region. Again 13x13 pixels

One further check:

micha@RMS RGI60-18 $ r.info RGI6018
 +----------------------------------------------------------------------------+
 | Map:      RGI6018                        Date: Tue Jul  9 10:13:28 2019    |
 | Mapset:   PERMANENT                      Login of Creator: micha           |
 | Location: test                                                             |
 | DataBase: /home/micha/work/tmp/RGI60-18/UTM60S                             |
 | Title:                                                                     |
 | Timestamp: none                                                            |
 |----------------------------------------------------------------------------|
 |                                                                            |
 |   Type of Map:  raster               Number of Categories: 0               |
 |   Data Type:    FCELL                                                      |
 |   Rows:         13                                                         |
 |   Columns:      13                                                         |
 |   Total Cells:  169                                                        |
 |        Projection: UTM (zone -60)                                          |
 |            N:  5651812.5    S:  5651487.5   Res:    25                     |
 |            E:   374962.5    W:   374637.5   Res:    25                     |
 |   Range of data:    min = 0  max = 35.92583                                |
 |                                                                            |
 |   Data Description:                                                        |
 |    generated by r.in.gdal                                                  |
 |                                                                            |
 |   Comments:                                                                |
 |    r.in.gdal input="RGI60-18.00001_thickness.tif" output="RGI6018" memo\   |
 |    ry=300 offset=0 num_digits=0                                            |
 |                                                                            |
 +----------------------------------------------------------------------------+

Again 13x13 pixels, with values from 0 to 35.9. As far as I can see, everything is fine. The pixels that are colored purple have value 0. (I would note that what you see in the Windows Viewer is irrelevant here)

  • Creating a new location with the tiff coordinates solved my problem. – Iced_ Jul 9 at 11:36

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