Let’s say in grass I have a raster layer “regionId” and a raster layer “forestArea”.
In the regionId I have stored the ids of the regions, in the forestArea I stored the square km of forest within the pixel.
How can I print a table summing up the forest area by region, that is the sum of the values of a layer aggregated (“group by”) by a second layer ?
Cheers,
Antonello
···
Antonello Lobianco
AgroParisTech, Laboratoire d’Economie Forestière
14 Rue Girardet - 54000 Nancy, France
Tel: +33.383396865
Email: antonello.lobianco@nancy.inra.fr
http://antonello.lobianco.org
Hei Antonello,
Have a look at r.univar (https://grass.osgeo.org/grass70/manuals/r.univar.html)
And the zone option.
Cheers
Stefan
···
Let’s say in grass I have a raster layer “regionId” and a raster layer “forestArea”.
In the regionId I have stored the ids of the regions, in the forestArea I stored the square km of forest within the pixel.
How can I print a table summing up the forest area by region, that is the sum of the values of a layer aggregated (“group by”) by a second layer ?
Cheers,
Antonello
–
Antonello Lobianco
AgroParisTech, Laboratoire d’Economie Forestière
14 Rue Girardet - 54000 Nancy, France
Tel: +33.383396865
Email: antonello.lobianco@nancy.inra.fr
http://antonello.lobianco.org
neteler
3
On Mon, Sep 19, 2016 at 6:41 PM, Antonello Lobianco
<antonello@lobianco.org> wrote:
Let's say in grass I have a raster layer "regionId" and a raster layer
"forestArea".
In the regionId I have stored the ids of the regions, in the forestArea I
stored the square km of forest within the pixel.
How can I print a table summing up the forest area by region, that is the
sum of the values of a layer aggregated ("group by") by a second layer ?
Please take a look at
https://grasswiki.osgeo.org/wiki/Zonal_statistics
There are several options.
Best
Markus
Thanks all to have pointed me to the right pages. I solved with the r.univar command:
r.univar -t map=forestArea zones=regionId separator=comma output=forestArea_by_region.csv
Cheers,
/Antonello
···
On 19 September 2016 at 21:59, Markus Neteler <neteler@osgeo.org> wrote:
On Mon, Sep 19, 2016 at 6:41 PM, Antonello Lobianco
<antonello@lobianco.org> wrote:
Let’s say in grass I have a raster layer “regionId” and a raster layer
“forestArea”.
In the regionId I have stored the ids of the regions, in the forestArea I
stored the square km of forest within the pixel.
How can I print a table summing up the forest area by region, that is the
sum of the values of a layer aggregated (“group by”) by a second layer ?
Please take a look at
https://grasswiki.osgeo.org/wiki/Zonal_statistics
There are several options.
Best
Markus
–
Antonello Lobianco
AgroParisTech, Laboratoire d’Economie Forestière
14 Rue Girardet - 54000 Nancy, France
Tel: +33.383396865
Email: antonello.lobianco@nancy.inra.fr
http://antonello.lobianco.org