Hello Laurent, You might want to check i.segment [0] within the core tools of GRASS and i.segment.uspo [1] for unsupervised parameter optimization within GRASS extensions. Also, there are nice papers by Grippa et al [2] and Georganos et al [3] that show the segmentation/OBIA workflow within GRASS.
To include texture rasters within segmentation, have a look at r.texture [4] tool in GRASS. What I usually do is to estimate textures from a panchromatic higher res band. hth, Vero [0] https://grass.osgeo.org/grass-stable/manuals/i.segment.html [1] https://grass.osgeo.org/grass-stable/manuals/addons/i.segment.uspo.html [2] https://doi.org/10.3390/rs9040358 [3] https://doi.org/10.3390/rs10091440 [4] https://grass.osgeo.org/grass-stable/manuals/r.texture.html El mar, 4 mar 2025 a las 12:20, Laurent CELATI via grass-user (< grass-user@lists.osgeo.org>) escribió: > > > Hello. > My goal is to generate a relevant segmentation that would delimit the main > physiopnomic units (homogenous areas). Up to now, I have done several tests > with qgis and orfeotoolbox 9 with the OTB Generic Region merging module : > GenericRegionMerging > — Orfeo ToolBox 7.0.0 documentation > <https://www.orfeo-toolbox.org/CookBook-7.0/Applications/app_GenericRegionMerging.html> > with those folowing settings > > - input image : spot 6/7 satelite image (band blue, green, red, near > infrared) > or Aerial french mapping agency images (50 cms bd ortho with green, > red and near infrared). > - Homogenity criterion to use : Baatz & Schape > - Threshold for the criterion : 500 > - Number of iterations`: 0 > - Weight for the spectral homogeneity : 0.1 > - Weight for the spatial homogeneity : 0.1 > > The result is rather interesting for certain areas, in particular crops > areas, without too much vegetation. on the other hand, the method does not > seems optimal, in particular for forest areas. > > Perhaps for these forest areas, the color/spectral criterion is not > relevant. It would be better to generate / integrate texture information? > As far as i understood, this GRM OTB module is based only on > spectral/colour criterion but not take into consideration texture > information. > Are there other qgis/grass/ orfeotoolbox or whatever other segmentation > module that takes into account not only the color criterion (spectral) but > also texture information? > If this is not the case, should i create some kind of new raster (add a > band to my existing color infrared raster) dedicated to texture and/or ndvi > information? > Thanks so much for your guidances. > _______________________________________________ > grass-user mailing list > grass-user@lists.osgeo.org > https://lists.osgeo.org/mailman/listinfo/grass-user > -- Dra. Verónica Andreo Investigadora Adjunta de CONICET Instituto Gulich (CONAE - UNC) Centro Espacial Teófilo Tabanera (CETT) Falda del Cañete - Córdoba, Argentina +54 3547 400000 int. 1153 https://veroandreo.gitlab.io/
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