This tool will identify the catchment areas to each link in a user-specified stream network, i.e. the network's sub-basins. subbasins effectively performs a stream link ID operation (stream_link_identifier) followed by a watershed operation. The user must specify the name of a flow pointer (flow direction) raster (`d8_pntr`), a streams raster (`streams`), and the output raster (`output`). The flow pointer and streams rasters should be generated using the d8_pointer algorithm. This will require a depressionless DEM, processed using either the breach_depressions_least_cost or fill_depressions tool.

hillslopes are conceptually similar to sub-basins, except that sub-basins do not distinguish between the right-bank and left-bank catchment areas of stream links. The Sub-basins tool simply assigns a unique identifier to each stream link in a stream network.

By default, the pointer raster is assumed to use the clockwise indexing method used by WhiteboxTools. If the pointer file contains ESRI flow direction values instead, the `esri_pntr` parameter must be specified.

NoData values in the input flow pointer raster are assigned NoData values in the output image.

## See Also

stream_link_identifier, watershed, hillslopes, d8_pointer, breach_depressions_least_cost, fill_depressions

## Function Signature

`def subbasins(self, d8_pntr: Raster, streams: Raster, esri_pntr: bool = False) -> Raster: ...`

## Project Links

WbW Homepage User Manual Support WbW