Flow accumulation

Dialog box

The Flow accumulation operation performs a cumulative count of the number of pixels that naturally drain into outlets. The operation can be used to find the drainage pattern of a terrain.

As input the operation uses the output map of the Flow direction operation.
The output map contains cumulative hydrologic flow values that represent the number of input pixels which contribute any water to the outlets (or sinks if these have not been removed).

Dialog box options:

Flow direction map:

Select an input raster map. Open the list box and select the desired input map, or directly drag a raster map from a Catalog into this box.

The input map should be an output map of the Flow direction operation, i.e. a map with system domain FlowDirection.

Output raster map:

Type a name for the output raster map that will contain the cumulative hydrologic flow values.

Description:

Optionally, type a description for the output map. The description will appear in the status bar of the Main window when moving the mouse pointer over the map in a Catalog, and in the title bar of a map window when the output map is displayed. If no description is supplied, the output map will use its 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.