Computes statistics on a training polygon set.
Process a set of geometries intended for training (they should have a field giving the associated class). The geometries are analyzed against a support image to compute statistics:
- Number of samples per class
- Number of samples per geometry
An optional raster mask can be used to discard samples. Different types of geometry are supported: polygons, lines, points. The behaviour is different for each type of geometry:
- Polygon: select pixels whose center is inside the polygon
- Lines: select pixels intersecting the line
- Points: select closest pixel to the point
This application has several output images and supports “multi-writing”. Instead of computing and writing each image independently, the streamed image blocks are written in a synchronous way for each output. The output images will be computed strip by strip, using the available RAM to compute the strip size, and a user defined streaming mode can be specified using the streaming extended filenames (type, mode and value). Note that multi-writing can be disabled using the multi-write extended filename option: &multiwrite=false, in this case the output images will be written one by one. Note that multi-writing is not supported for MPI writers.
-in image Mandatory
Support image that will be classified
Input validity mask
Validity mask (only pixels corresponding to a mask value greater than 0 will be used for statistics)
-vec filename [dtype] Mandatory
Input geometries to analyze
Output XML statistics file
-out filename [dtype] Mandatory
Output file to store statistics (XML format)
Name of the field carrying the class name in the input vectors.
-layer int Default value: 0
Layer index to read in the input vector file.
This group of parameters allows managing elevation values. Supported formats are SRTM, DTED or any geotiff. DownloadSRTMTiles application could be a useful tool to list/download tiles related to a product.
This parameter allows selecting a directory containing Digital Elevation Model files. Note that this directory should contain only DEM files. Unexpected behaviour might occurs if other images are found in this directory.
-elev.geoid filename [dtype]
Use a geoid grid to get the height above the ellipsoid in case there is no DEM available, no coverage for some points or pixels with no_data in the DEM tiles. A version of the geoid can be found on the OTB website(https://gitlab.orfeo-toolbox.org/orfeotoolbox/otb-data/blob/master/Input/DEM/egm96.grd).
-elev.default float Default value: 0
This parameter allows setting the default height above ellipsoid when there is no DEM available, no coverage for some points or pixels with no_data in the DEM tiles, and no geoid file has been set. This is also used by some application as an average elevation value.
Available RAM (MB)
-ram int Default value: 256
Available memory for processing (in MB).
From the command-line:
otbcli_PolygonClassStatistics -in support_image.tif -vec variousVectors.sqlite -field CLASS -out polygonStat.xml
import otbApplication app = otbApplication.Registry.CreateApplication("PolygonClassStatistics") app.SetParameterString("in", "support_image.tif") app.SetParameterString("vec", "variousVectors.sqlite") app.SetParameterString("field", "CLASS") app.SetParameterString("out", "polygonStat.xml") app.ExecuteAndWriteOutput()