* Markus Neteler <nete...@osgeo.org> [2018-04-15 22:49:09 +0200]:

On Sun, Apr 15, 2018 at 9:46 PM, Markus Neteler <nete...@osgeo.org> wrote:
On Sun, Apr 15, 2018 at 8:48 PM, Veronica Andreo <veroand...@gmail.com> wrote:
Hi devs,

I just found something odd. I have a CHIRPS tif for Africa [0], but I would
only need to import Ghana, so I used r.in.gdal -r. However when I visualize
the data, most of it is nodata, while the full map of Africa has data all
over the continent. Then, I tried also with r.import extent=region. Same
result. The only thing providing what I expected to be the right result (a
subset from the full map) is importing the whole map and then using
r.mapcalc to clip (i need the space in my hard disk)

trying harder I can reproduce the issue (of course not NULL related).

So, I have no clue right now why it behaves differently.


no intention to add noise. There is something weird, here too.

# first things first
grass -c /geo/geodata/examples/chirps-v2.0.2018.01.01.tif 

# importing the whole map looks visually ok
r.in.gdal input=/geo/geodata/examples/chirps-v2.0.2018.01.01.tif 

# then, using the following box coordinates for Ghana from
# https://en.wikipedia.org/wiki/User%3aThe_Anome/country_bounding_boxes
g.region w=-4.000 e=4.733 n=20.000 s=11.167 -p

# to draw the box on-display
v.in.region output=ghana_box

# and doing a partial import
r.in.gdal -r input=/geo/geodata/examples/chirps-v2.0.2018.01.01.tif 

Regardless whether the box figures are not correct, while the imported
portion is, indeed, a box fraction of the whole map, it isn't, visually
the "right" part. It appears as a part from the coast has been imported.

I am double-checking the steps I followed, I always get the same.


grass-dev mailing list

Reply via email to