<div dir="ltr"><div dir="ltr">Hello Laurent, <div><br></div><div>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.</div><div><br></div><div>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. </div><div><br></div><div>hth, </div><div>Vero</div><div><br></div><div>[0] <a href="https://grass.osgeo.org/grass-stable/manuals/i.segment.html" target="_blank">https://grass.osgeo.org/grass-stable/manuals/i.segment.html</a></div><div>[1] <a href="https://grass.osgeo.org/grass-stable/manuals/addons/i.segment.uspo.html" target="_blank">https://grass.osgeo.org/grass-stable/manuals/addons/i.segment.uspo.html</a></div><div>[2] <a href="https://doi.org/10.3390/rs9040358" target="_blank">https://doi.org/10.3390/rs9040358</a></div><div>[3] <a href="https://doi.org/10.3390/rs10091440" target="_blank">https://doi.org/10.3390/rs10091440</a></div><div>[4] <a href="https://grass.osgeo.org/grass-stable/manuals/r.texture.html" target="_blank">https://grass.osgeo.org/grass-stable/manuals/r.texture.html</a></div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">El mar, 4 mar 2025 a las 12:20, Laurent CELATI via grass-user (<<a href="mailto:grass-user@lists.osgeo.org">grass-user@lists.osgeo.org</a>>) escribió:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg7438147558696578486">
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<p class="MsoNormal"><span>Hello.<br>
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 :
<a href="https://www.orfeo-toolbox.org/CookBook-7.0/Applications/app_GenericRegionMerging.html" target="_blank">
<span style="color:blue">GenericRegionMerging — Orfeo ToolBox 7.0.0 documentation</span></a> with those folowing settings<u></u><u></u></span></p>
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<span>input image : spot 6/7 satelite image (band blue, green, red, near infrared)<br>
or Aerial french mapping agency images (50 cms bd ortho with green, red and near infrared).<u></u><u></u></span></li><li class="MsoNormal">
<span>Homogenity criterion to use : Baatz & Schape<u></u><u></u></span></li><li class="MsoNormal">
<span>Threshold for the criterion : 500<u></u><u></u></span></li><li class="MsoNormal">
<span>Number of iterations`: 0<u></u><u></u></span></li><li class="MsoNormal">
<span>Weight for the spectral homogeneity : 0.1<u></u><u></u></span></li><li class="MsoNormal">
<span>Weight for the spatial homogeneity : 0.1<u></u><u></u></span></li></ul>
<p class="MsoNormal"><span>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.<br></span></p></td></tr></tbody></table><p class="MsoNormal"><span>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.<br>
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?<br>
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?<br>
Thanks so much for your guidances.</span><u></u><u></u></p>
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</div></blockquote></div><div><br clear="all"></div><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr"><font color="#888888">Dra. Verónica Andreo<br>Investigadora Adjunta de CONICET<br></font><div><font color="#888888">Instituto Gulich (CONAE - UNC)<br></font></div><div><font color="#888888">Centro Espacial Te</font><font color="#888888"><font color="#888888">ó</font>filo Tabanera (CETT)</font><br></div><font color="#888888">Falda del Cañete - Córdoba, Argentina<br></font><div><font color="#888888">+54 3547 400000 int. 1153</font></div><div><font color="#888888"><a href="https://veroandreo.gitlab.io/" target="_blank">https://veroandreo.gitlab.io/</a><br></font></div></div></div></div>