Since Chanel network is a SAGA-GIS algorithm it is vital to get some knowledge on how this application is handling the data.
In SAGA's environment most of the grid calculations are being made within the one/same Grid System. The Grid System is SAGA's way of grouping loaded grids - in a simple words it groups adjacent grids. By adjacent you should understand grids that have:
- the same cell size,
- the same resolution (height px / width px),
- the same spatial extent (basically the same x,y coordinates of most-western, most-southern corner).
So, in order to run this tool you need to pre-process your data - use some clipping and/or resampling tools in order to get a proper (same Grid System) input data for Chanel network algorithm.