Area numbering assigns unique identifiers to pixels with the same class names or IDs that are horizontally, vertically or diagonally connected.
The output of Area numbering is a map in which these connected areas are codified as Area 1, Area 2, etc. Furthermore, an attribute table is created for the output map. The table contains the new IDs; the class names or IDs of the original mapping units; and the size (npix and area) of the unique output units.
Area numbering can be used to make a decision based on the size of individual groups of pixels with the same class name or ID (uniquely identified areas) instead of on all pixels with the same class name or ID.
Dialog box options:
Input raster map: |
Select an input raster map. Open the list box and select the desired input map, or drag a raster map directly from the Catalog into this box. In the dialog box, you can only select a map with a class, ID or Bool domain; on the command line you can also use input value maps. |
Connect: |
Select option button 4 to retrieve 4-connected areas, i.e. areas will be constructed for pixels with the same pixel value which are horizontally or vertically connected. Select option button 8 to retrieve 8-connected areas, i.e. areas will be constructed for pixels with the same pixel value which are horizontally, vertically or diagonally connected. |
Output raster map: |
Type a name for the output raster map that will contain the renumbered connected areas. This name will also be used for the output attribute table. |
Description: |
Optionally, type a description for the output map and the output table. The description will appear in the status bar of the Main window when moving the mouse pointer over the map or table in a Catalog, and in the title bar of a map or table window when the output map or table is displayed. If no description is supplied, the output map and the table will use their own definition as description. |
When you click the Show button, the dependent output map will be defined, calculated and shown. When you click the Define button, the dependent output map will only be defined; if necessary the map will be calculated later, for instance when the map is opened to be displayed.
Furthermore, an attribute table will be defined which will contain the names of the original mapping units, the number of pixels and the areas of the unique output units.
Both the output map and the attribute table will use a UniqueID domain.
See also: