[GRASS-user] Flow direction to flow accumulation

Hello all,
Does GRASS have a tool equivalent to what ArcGIS calls Flow Accumulation? Input is a flow direction raster and output is a cumulative catchment area raster. As an optional argument you can specify a weight raster, which is really important for what I am trying to do - count cells of woodland upstream from each cell in the flow direction grid.

All GRASS tools I thought could do this require DTM as input, not flow direction raster, and they also don’t allow to specify the weight raster. As far as I can see.

Do you know about any other OSGeo tools that could do this? Ideally Python friendly?
Best regards,
Filip Kral.

Filip,

Yes; look at the GRASS raster commands: r.terraflow, r.watershed

Tom

···

On Thu, Nov 19, 2015 at 5:02 PM, wcd <vydramail@quick.cz> wrote:

Hello all,
Does GRASS have a tool equivalent to what ArcGIS calls Flow Accumulation? Input is a flow direction raster and output is a cumulative catchment area raster. As an optional argument you can specify a weight raster, which is really important for what I am trying to do - count cells of woodland upstream from each cell in the flow direction grid.

All GRASS tools I thought could do this require DTM as input, not flow direction raster, and they also don’t allow to specify the weight raster. As far as I can see.

Do you know about any other OSGeo tools that could do this? Ideally Python friendly?
Best regards,
Filip Kral.


grass-user mailing list
grass-user@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/grass-user

Thomas E Adams, III
2330 Jack Warner PKWY, #334
Tuscaloosa, AL 35401

1 (513) 739-9512 (cell)

As far as I can see, you have one option: r.drain creates drainage lines based on a flow direction grid and and input grid (“weight” raster). With the “-a” flag the total weights are placed into the output cells. But this module gives you accumulation only along the drainage lines, NOT a full flow accumulation grid.

···

On 11/20/2015 01:02 AM, wcd wrote:

Hello all,
Does GRASS have a tool equivalent to what ArcGIS calls Flow Accumulation? Input is a flow direction raster and output is a cumulative catchment area raster. As an optional argument you can specify a weight raster, which is really important for what I am trying to do - count cells of woodland upstream from each cell in the flow direction grid.

All GRASS tools I thought could do this require DTM as input, not flow direction raster, and they also don’t allow to specify the weight raster. As far as I can see.

Do you know about any other OSGeo tools that could do this? Ideally Python friendly?
Best regards,
Filip Kral.

This mail was received via Mail-SeCure System.

_______________________________________________
grass-user mailing list
[grass-user@lists.osgeo.org](mailto:grass-user@lists.osgeo.org)
[http://lists.osgeo.org/mailman/listinfo/grass-user](http://lists.osgeo.org/mailman/listinfo/grass-user)
This mail was received via Mail-SeCure System.

Micha Silver
Arava Drainage Authority
+972-523-665918