Maybe I could clarify. Here's the command: *v.kernel --verbose input=master_grass7 output=master_grass7a_heatmap stddeviation=.0001*
Here's the command output: *STDDEV: 0.000100* *RES: 200.000000 ROWS: 1000 COLS: 1000* * * *Writing output raster map using smooth parameter=0.000100.* * * *Normalising factor=0.000000.* *Maximum value in output: 0.000000e+000.* If I change stddeviation to *100*, here's what I get: *STDDEV: 100.000000* *RES: 200.000000 ROWS: 1000 COLS: 1000* * * *Writing output raster map using smooth parameter=100.000000.* * * *Normalising factor=64826.350188.* *Maximum value in output: 0.000000e+000.* Either way, the resulting raster is a large salmon/pink square. I have no idea what I'm doing wrong. I've tried varying the *stddeviation *parameter from 100 to .0001 and some values in between, and I don't get anything different. Heck, I just now used 1000000 and .000001 and got nothing different. I was really hoping to make a high res heat map of these 2.5 million points and overlay on to a street map layer. Aren On Fri, Feb 11, 2011 at 9:45 PM, Aren Cambre <a...@arencambre.com> wrote: > I am not clear how to get useful results out of v.kernel. I have a vector > layer imported from PostGIS that has about 2.5 million points. I want to > make a high density raster to show where these points are clustered. I can > get the vector layer to display in GRASS just fine, albeit without > attributes because of http://trac.osgeo.org/grass/ticket/1274. > > It's not clear to me, based on > http://grass.fbk.eu/gdp/html_grass64/v.kernel.html, how you can get it to > do something besides make a big, pinkish (salmon-red?) square? > > Aren >
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