[GRASS-user] Re: ANUDEM HUTCHINSON TopoToRaster equivalent in GRASS

RODEO gregnalice at yahoo.com
Sat Mar 5 15:05:31 EST 2011

A little info on how we are processing the DEMs (BELOW), and in step 5 you
will see we use TopoToRaster.

We need to move to the GRASS GIS, and will not have TopoToRaster, so we are
attempting to reproduce this methodology in GRASS if possible. 

So, is there an equivalent in GRASS to how we were using TopoToRaster in the
methodology below:

1.        Using the original DEMs flow direction grid, run the flow
accumulation function for the region, using a weight grid to produce results
in square kilometers (rather than just a pixel count).

2.        Select flow accumulation values with a 10-km2 threshold or greater
value to create a stream mask.

3.        Convert  the stream mask to unique stream links & convert the
links to a feature dataset.

4.        Using the raw (unburned) SRTM, convert this dataset to a point
dataset (one point for every cell in the DEM).

5.        Running on a buffered 1-degree tile, use the TopoToRaster
algorithm, with inputs of the stream lines & the raw SRTM points, to create
a minimally burned DEM.  

6.        Fill this DEM to remove spurious sinks (maintaining natural sinks
that were identified in the original DEM processing).

7.        Clip each of the results from the buffered 1-degree tiles back to
1-degree exactly and merge all tiles together.

8.        Fill this merged DEM, generate flow directions, weighted flow
accumulations and streams.

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