Method to derive Sea Draining Catchments from LINZ 8m DEM. Output is a single GPKG file containing only non-overlapping sea draining catchments. In this method, the largest catchment in a region is used.
This method begins with downsampling the LINZ 8m to 100m resolution.
The LINZ 8m DEM can be found here
Downsample LINZ 8m
make select
Create all catchments
make catchment
Filter to only sea draining catchments
make sea-drain