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I can't make 'D8 Slope Grid' work in QGIS-Sextante. 'Pit Filled' and 'D8 Flow Direction Grid' output work okay.
I used the function: Geoalgorithms > Uncategorized > Basic Grid Analysis tools > D8 Flow Directions inside Sextante Box. Then I filled out the required parameters.
What have I missed? Any help is appreciated.
Thanks. - Al

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What was the output or error message after you completed that dialog? –  whuber Apr 1 '13 at 21:44
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I think the D8 Slope Grid is not giving correct display. I can only see 2 colors. Expanding the layer, I see the slope ranges from 0 to 28. (Although the histogram shows that 0 frequency is quite high.) I've tried different options, e.g. grayscale, pseudocolor, colormap, as well as contrast enhancement and several classification modes - without luck. The 'Identify Features' tool, however, shows varying slope values for the non-zero slope areas. Is there a way to display the non-zero slopes in different colors? Thanks for your help. –  Alejandro Apr 9 '13 at 18:46

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