2. Classification dilation

_images/classification_dilation_tab.jpg

classification_dilation Classification dilation

This tab allows for dilating the border of a class patch, defining the class values to be dilated and the number of pixels from the border. It is useful for classification refinement.

This tool supports virtual raster output; if the output file name ends with .vrt then the output is created as virtual raster composed of as many .tif files as the number of CPU threads defined in System; for large rasters this can speed up the process.

2.1. Classification dilation

  • Select the classification input_list: select a raster (already loaded in QGIS);

  • reload: refresh layer list;

  • Class values input_text: set the class values to be dilated; class values must be separated by , and - can be used to define a range of values (e.g. 1, 3-5, 8 will select classes 1, 3, 4, 5, 8); if the text is red then the expression contains errors;

  • Size in pixels input_number: number of pixels to be dilated from the border;

  • checkbox Circular optional: if checked, the dilation will be circular, similar to a buffer;

  • BATCH batch_tool: add this function to the Batch;

  • RUN run: choose the output destination and start the calculation;