<div dir="ltr">Hi Raul,<div><br></div><div>You should set the origin on writers.gdal in order to get the consistency you desire. Without this, the origin is set according to the first point processed, which may differ between pipelines.</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Jun 20, 2024 at 4:24 AM Raúl Casado Barbero via pdal <<a href="mailto:pdal@lists.osgeo.org">pdal@lists.osgeo.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><u></u>

  

    
  
  <div>
    <p>Hi,</p>
    <p>my aim is to calculate the fitovolume of a shrub vegetation area.
      To do that I calculate the DSM, classify a point cloud with ground
      (2) and low vegetation (3) and then create a DTM.</p>
    <p>I use 2 different pipelines (see below) to do that modified from
      <a href="https://github.com/manaakiwhenua/pycrown/issues/18" target="_blank">this
        post</a>. But I have 2 issues:</p>
    <ul>
      <li>When I calculate the difference between DSM and DTM I get
        negative values</li>
      <li>The pixels of the DTM are horizontally displaced with respect
        to the DSM by half a pixel.</li>
    </ul>
    <p>Does anyone know why I am getting these negative values using
      this pipelines? Is anything wrong in the pipelines I`m using?<br>
      <br>
      <br>
      Raúl.<br>
      <br>
      Pipeline for DSM:<br>
      <br>
      [<br>
          "nubeRecortadaPdal_1.laz",<br>
          {<br>
              "type": "filters.range",<br>
              "limits":"returnnumber[1:1]"<br>
          },<br>
          {<br>
              "type": "writers.gdal",<br>
              "filename": "nubeRecortadaPdal_1_mds.tif",<br>
              "output_type": "idw",<br>
              "gdaldriver": "GTiff",<br>
              "resolution": 0.05, <br>
              "nodata": -9999,<br>
              "radius": 0.07,<br>
              "window_size": 50,<br>
              "data_type": "float32"<br>
          }<br>
      ]<br>
      <br>
      Pipeline for DTM:<br>
      <br>
      [<br>
          "nubeRecortadaPdal_1.laz",<br>
          {<br>
              "type":"filters.overlay",<br>
              "dimension":"Classification",<br>
              "datasource":"D:/Datos/clasificadasVector.gpkg",<br>
              "layer":"ndviRandomForest",<br>
              "column":"Id"<br>
          },<br>
          {<br>
              "type":"filters.range",<br>
              "limits":"Classification[2:2]"<br>
          },<br>
          {<br>
              "type": "writers.gdal",<br>
              "filename": "nubeRecortadaPdal_1_mdt_ndviRf.tif",<br>
              "output_type": "idw",<br>
              "gdaldriver": "GTiff",<br>
              "resolution": 0.05, <br>
              "nodata": -9999,<br>
              "radius": 0.07,<br>
              "window_size": 100,<br>
              "data_type": "float32"<br>
          }<br>
      ]</p>
    <br>
  </div>

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</blockquote></div><br clear="all"><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature">Andrew Bell<br><a href="mailto:andrew.bell.ia@gmail.com" target="_blank">andrew.bell.ia@gmail.com</a></div>