This tool can be used to identify the 'catchment area' of each source grid cell in a cost-distance analysis. The user must specify the names of the input source and back-link raster files. Source cells (i.e. starting points for the cost-distance or least-cost path analysis) are designated as all positive, non-zero valued grid cells in the source raster. A back-link raster file can be created using the cost_distance tool and is conceptually similar to the D8 flow-direction pointer raster grid in that it describes the connectivity between neighbouring cells on the accumulated cost surface.

NoData values in the input back-link image are assigned NoData values in the output image.

## See Also

cost_distance, cost_pathway, euclidean_allocation

## Function Signature

`def cost_allocation(self, source: Raster, backlink: Raster) -> Raster: ...`

## Project Links

WbW Homepage User Manual Support WbW