Ciao Madi, Vero,

Starting with GRASS 7.6, also centroids are used to get the raster 
representation of your area vector map. That increases the likelihood of 
smaller areas to be rasterized.
Increasing the resolution of the current region alone does not help, because 
v.rast.stats temporarily changes the computational region to align with the 
input raster map(s) (see also: https://trac.osgeo.org/grass/ticket/3523 and 
https://trac.osgeo.org/grass/ticket/3598 for discussion) Even if the first 
ticket is closed, comments are welcome.
It might make sense to add a flag to v.rast.stats like in r.slope.aspect to not 
align the computational region.

Furthermore, with regards to efficiency, v.strds.stats could gain some speed if 
multi-raster support in v.rast.stats - added in G 7.6 - would be handed down to 
the addon. Might almost double the speed for larger STRDS…

Cheers
Stefan

From: grass-user <[email protected]> On Behalf Of Veronica 
Andreo
Sent: onsdag 6. februar 2019 17:20
To: Margherita Di Leo <[email protected]>
Cc: GRASS user list <[email protected]>
Subject: Re: [GRASS-user] sample a strds at specific locations (areas)

Hi Madi

El mié., 6 feb. 2019 a las 16:31, Margherita Di Leo 
(<[email protected]<mailto:[email protected]>>) escribió:
I have a question regarding v.strds.stats. I get the following warning message:

WARNING: Not all vector categories converted to raster. Converted 120 of 265.

What could be the reason for that?

Some vector areas might not be converted because they are too small with 
respect to the pixel size that you try to query. Others will tell better but I 
think the polygon must overlap the center of the pixel in order to be converted 
into raster. One solution could be to resample your rasters to a higher 
resolution.
HTH,
Vero
_______________________________________________
grass-user mailing list
[email protected]
https://lists.osgeo.org/mailman/listinfo/grass-user

Reply via email to