Deleting small regions

Deleting of raster region is understood as joining of regions which area is less than the specified tolerance to one of the neighboring areas. If the deleted region borders on one area, i.e. is located inside the other, and its size is less than tolerance, it always is joined to the neighboring area.

If the region borders on several regions, then joining is performed according to the priority defined in the table of the Priority of joining of neighboring areas. In this table the lines correspond to a deleted class, columns define classes to which the deleted class joins. To add a class admissible for joining, it is necessary to press the left mouse button in the appropriate cell of the table and to choose a class from the drop-down menu.

Example of filling the table of a priority of joining neighboring regions:

In this example the rivers never join other classes. Woods join the meadows and the indeterminate (not classified) regions. The meadow vegetation joins only indeterminate regions. Indeterminate regions join only meadow vegetation.

Raster of classification before deleting small regions:

Raster of classification after deleting small regions: