Fill sinks

Dialog box

The Fill sinks operation 'removes' local depressions (of single pixels and of multiple pixels) from a Digital Elevation Model (DEM).

The height value of a single-pixel depression is raised to smallest value of the 8 neighbours of a single-pixel depression.
The height values of a local depression consisting of multiple pixels are raised to the smallest value of a pixel that is both adjacent to the outlet for the depression, and that would discharge into the initial depression.

By using the Fill sinks operation,

and a subsequent Flow direction operation on the output map of the Fill sinks operation,
and a Flow accumulation operation on the output map of Flow direction operation,

it is ensured:

that a flow direction will be found for every pixel in the map, and
that water in any pixel will be discharged into outlets towards the edges of the map.

Dialog box options:

Input DEM:

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 is supposed to be a Digital Elevation Model (DEM).

Output raster map:

Type a name for the output raster map that will contain height values without local depressions.

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.

Tip: After using the Fill sinks operation, and before using the Flow direction and Flow accumulation operations, you can use the DEM optimization operation on the output DEM of the Fill sinks operation, to further improve your DEM.