Hi,
GRASS adjusts the resolution to the bounds (extent) you specified, either as n,
s, e, w coordinates (like in Processing) or using the “vector” or “raster”
option. This can conflicting with information provided through the user
specified resolution; meaning that either bounds or resolution
Hi Martin and Stefan,
I understand, if we do not use the -a flag, we can not ensure that the
resolution is the set.
What if there is another option, "align=", as Stefan suggested, which
allows to choose a raster from the canvas? This would ensure that the
region would be aligned with a selected
Von: Qgis-developer [qgis-developer-boun...@lists.osgeo.org] im Auftrag von
gene [martin.lal...@gmail.com]
Gesendet: Samstag, 12. März 2016 10:46
An: qgis-developer@lists.osgeo.org
Betreff: Re: [Qgis-developer] Problem with GRASS Region Extent and Region
To keep the raster resolution.
In the book "OPEN SOURCE GIS A GRASS GIS Approach Third Edition", p.57
"It may happen, that region boundaries lead to a modified, non-integer
raster resolution. If this is not desired, the -a flag can be used to align
the region to resolution. It adjusts all four
Hi Martin,
Thank you very much for the hint.
So, runing an operation and aligning the result to a raster with a smaller
extent:
g.proj -c proj4="+proj=tmerc +lat_0=39.668258
+lon_0=-8.1331084 +k=1 +x_0=0 +y_0=0 +ellps=GRS80
+towgs84=0,0,0,0,0,0,0 +units=m +no_defs"
r.external
You can control what the algorithm is doing by viewing the resulting files
- /.../.qgis2/processing/grass_batch_job.sh (or .bat) for GRASS 6.4.x
- /.../.qgis2/processing/grass7_batch_job.sh (or .bat) for GRASS 7.x
They are created by the scripts
Hi,
I've been doing some tests on Processing and found something strange with
the GRASS tools, using GRASS Region Extent and Region Cellsize options.
These options work well when doing an operation that aligns the result to a
raster with a smaller extent. Please see this screencast:
