Sorry, I transposed the links. The top link is the results using r.terraflow in r.landscape.evol, and the bottom link is the results using r.watershed, not vice versa. Also, I should note that these maps are the absolute value of the 10th year dem with smoothing enabled minus the 10th year dem with no smoothing.
On 12/3/08, Isaac Ullah <[EMAIL PROTECTED]> wrote: > > Here are some additional results of testing between new version of > r.watershed and r.terraflow. > > *Time costs:* > > Map A (2.8 million cells), r.watershed is 52 seconds faster than > r.terraflow > > Map B (21 millions cells), r.watershed is 2 minutes 58 seconds faster than > r.terraflow > > *Accuracy in r.landscape.evol simulations:* > > Maps produced using r.watershed for flowacc show realistic values of > erosion and deposition *with no smoothing* after 10 model cycles(1 cycle = > 1 sim year). The difference between smoothed and unsmoothed maps is at > maximum only .5 meters, and the diffs are dispersed topographically. Image > link: > http://www.public.asu.edu/~iullah/files/MEDLAND/smo_nosmo_diff_terraflw.png > > Maps produced using r.terraflow for flowacc show spikes as high as +/- 96 > meters (with no smoothing) after 10 model cycles. Spikes are concentrated in > the channels, and diff between smoothed and un smoothed results also show > anamolies are concetrated in the channels. Image link: > http://www.public.asu.edu/~iullah/files/MEDLAND/smo_nosmo_diff_rwshd.png > > I am currently testing new r.watershed in a longterm model run (100 cycles) > with no smoothing, and will report the results here. In r.lnadscape.evol for > a 2.8 million cell map, the smoothing routine costs 23.5 seconds. Using new > r.watershed with the smoothing turned on takes 1 minute 5.5 seconds. Without > smoothing takes only 42 seconds. Using r.terraflow with smoothing takes 1 > min 57 seconds. Using r.terraflow without smoothing takes 1 minute 33 > seconds, but produces unusable results. Also, using r.watershed eliminates > the need to run r.fill.dir before each model run--an additional time > savings... > > Cheers > -- > > Isaac I Ullah, M.A. > > Archaeology PhD Student, > ASU School of Evolution and Social Change > > Research Assistant, > Mediterranean Landscape Dynamics Project > *************************************************** > [EMAIL PROTECTED] > [EMAIL PROTECTED] > > http://www.public.asu.edu/~iullah > *************************************************** -- Isaac I Ullah, M.A. Archaeology PhD Student, ASU School of Evolution and Social Change Research Assistant, Mediterranean Landscape Dynamics Project *************************************************** [EMAIL PROTECTED] [EMAIL PROTECTED] http://www.public.asu.edu/~iullah ***************************************************
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