Check if gdal_calc.py Python script is available.
Details
The gdal_calc.py Python script is used to process Area of Habitat data
when using the GDAL engine (within create_spp_aoh_data()) .
This function determines if this script is available on the system.
On Windows systems, it first tries to access this script using the
OSGeo4W software (available at https://trac.osgeo.org/osgeo4w/).
If that fails, or if you are not using a Windows system: it then tries to
access this script using default system variables.
Examples
# see if gdal_calc python script is available
print(is_gdal_calc_available())
#> [1] TRUE