[Qgis-user] gdaldem plugin versus raster terrain modelling plugin

[maning sambale]

Currently we have two terrain analysis plugin, one for as a core
plugin (Raster Terrain Modelling) and the other in GdalTools
(gdaldem).

The Raster Terrain Modelling has 4 analysis algorithm (slope, aspect,
ruggedness, total curvature) and has simpler UI (analysis type, input,
output, output format).  On the other hand, gdaltools' dem analysis
has more algorithms (hillshade, slope, aspect, color-relief, TRI, TPI,
roughness) and parameter switches (i.e. for Slope, scale factor).

I tested the generation of both plugin on the same DEM and I got
different results.  Visually inspecting the map, the results looks
very similar.  But the data stats while not very divergent, are
different, see below.

$ gdalinfo -hist slope_terrainplugin.tif
<snip>
  Metadata:
    STATISTICS_MAXIMUM=88.384605407715
    STATISTICS_MEAN=10.562942081774
    STATISTICS_MINIMUM=0
    STATISTICS_STDDEV=10.476060265591

$ gdalinfo -hist slope_gdalplugin.tif
<snip>
  Metadata:
    STATISTICS_MAXIMUM=87.754096984863
    STATISTICS_MEAN=10.702959382095
    STATISTICS_MINIMUM=0
    STATISTICS_STDDEV=10.367163780773

I'm asking here for experience of people in using the two plugins,
which of the two has better results in your analysis?  FWIW, you can
also include GRASS' r.slope.aspect in the comparison.
-- 
cheers,
maning
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