[Qgis-developer] plans to integrate terrain analysis tools? (was: Fwd: gdaldem plugin versus raster terrain modelling plugin)

Marco Hugentobler marco.hugentobler at sourcepole.ch
Fri May 4 01:52:04 PDT 2012

Hi Maning

The discussion is open. I'm of course biased towards the raster terrain 
plugin (and plan to support it also in the future).

The raster terrain plugin has some new functions in 1.8:
- hillshade
- relief creation algorithm (see 
- z factor (to handle lat/long datasources)

Planned in future is the possibility to give output options (e.g. 


Am 04.05.2012 10:26, schrieb maning sambale:
> Dear devs,
> What are the immediate plans to integrate terrain/dem tools?
> Currently we have several terrain tools available (Raster Terrain
> Modelling plugin, GdalTools, GRASS, Sextante).
> I am currently preparing a howto on terrain analysis for newbies and I
> am evaluating which of the above plugin to introduce.  Perhaps if
> there are plans to integrate, I might as well introduce them to the
> plugin the will eventually "survive" the integration.
> Thanks!
> ---------- Forwarded message ----------
> From: maning sambale<emmanuel.sambale at gmail.com>
> Date: Thu, Apr 26, 2012 at 3:52 PM
> Subject: gdaldem plugin versus raster terrain modelling plugin
> To: qgis-user<qgis-user at lists.osgeo.org>
> 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_STDDEV=10.476060265591
> $ gdalinfo -hist slope_gdalplugin.tif
> <snip>
>   Metadata:
>     STATISTICS_MAXIMUM=87.754096984863
>     STATISTICS_MEAN=10.702959382095
>     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
> ------------------------------------------------------
> "Freedom is still the most radical idea of all" -N.Branden
> wiki: http://esambale.wikispaces.com/
> blog: http://epsg4253.wordpress.com/
> ------------------------------------------------------

Dr. Marco Hugentobler
Sourcepole -  Linux&  Open Source Solutions
Weberstrasse 5, CH-8004 Zürich, Switzerland
marco.hugentobler at sourcepole.ch http://www.sourcepole.ch
Technical Advisor QGIS Project Steering Committee

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