The concept of REGION makes GRASS efficient for performing analysis
and modeling using data layers with various spatial extent and resolution.
Most of the GRASS commands are performed on the subset of the data
defined by the current region.
The current region can be defined using
for example, the current region can be set to the extent of a raster file:
To change the current resolution to 10m without changing the spatial extent:
or interactively within the graphic display by
g.region rast=elevation -p
g.region res=10