I have recently been struggling with an issue in GRASS. I am a new GRASS user and recently downloaded version 7.8.5 for my MacBook (macOS Catalina). I converted this sample dataset to a shapefile. I am able to load and visualize the file and set the region to be the set of points. When I run v.surf.idw, I get the following error:

Input vector map <coal_test@PERMANENT> is 2D - using categories to interpolate
WARNING: No record for point (cat = 1)
WARNING: No record for point (cat = 2)
WARNING: No record for point (cat = 3)
WARNING: No record for point (cat = 96)
0 points loaded
ERROR: No points found

I have tried to use v.surf.idw with different datasets as well and am still getting the same error. I've also tried re-installing GRASS GIS to no avail.

  • can you share the command line you enter? or the values you are entering at the interface?
    – Elio Diaz
    Feb 12, 2021 at 0:38

1 Answer 1


I have tried with your dataset as per https://lists.osgeo.org/pipermail/grass-user/2021-February/082215.html, it does work. The step which you are missing is to first set the computational region to the dataset (https://grasswiki.osgeo.org/wiki/Computational_region).

Since I agree that the current error message is unhelpful, I have proposed a modification (see here).


# set computational region to vector map, target raster resolution to 10m and 
# -a align to rounded coordinates
g.region vector=coal_test -p res=10 -a

# interpolate vector points to raster map
v.surf.idw input=coal_test output=coal_test_tested
Input vector map <coal_test@PERMANENT> is 2D - using categories to
81 points loaded
Interpolating raster map <coal_test_tested> (150 rows, 150 columns)...
v.surf.idw complete.

# compute univariate statistics of new raster map
r.univar -e coal_test_tested
total null and non-null cells: 22500
total null cells: 0

Of the non-null cells:
n: 22500
minimum: 8.07871
maximum: 94.9344
range: 86.8557
mean: 49.5003
mean of absolute values: 49.5003
standard deviation: 23.965
variance: 574.319
variation coefficient: 48.4138 %
sum: 1113756.87386977
1st quartile: 27.2997
median (even number of cells): 49.6119
3rd quartile: 70.95
90th percentile: 82.4886

Result (use a different target resolution as needed or a different interpolation method): enter image description here

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.