Using SAGA Raster Calculator on QGIS - a quick tutorial

The SAGA Raster calculator is useful because it allows to make some calculations that the regular QGIS Raster Calculator does not. Especially, it allows us to use the X and Y coordinates of the raster as inputs for our calculations. How do we start?

When I mosaic two rasters, the size of the resulting raster is almost always larger than the sum of the sizes of the original rasters. Why is that?

Short answer: your GIS software needs to fill the blanks in the area with NoData pixels. Long answer: I will demonstrate what happens by an example on QGIS 3.18, and show why the final raster tends to be larger than the other two summed.

Solved: SAGA GIS 7.9.0 and 2.3.2 (in QGIS) input error “Error: Catchment Area” on the execution of LS Factor “saga_cmd ta_hydrology 22” and other algorithms

Last week, we talked a little about using SAGA on Command Line. Today, I am discussing solutions to the problem “Error: Catchment Area” on SAGA GIS. Or “Error: your input raster”, or “Input layers do not have the same grid extent”.

How to use SAGA GIS Command Line saga_cmd, and why?

SAGA also has its own Graphical User Interface (GUI). And it also has its own Command Line version. One may ask, why would someone deliberately choose to use a Command Line version in detriment of a GUI? Well, a GUI uses its own share of memory, CPU, sometimes GPU, to run.