WCPS-Tutorial / Combining coverages
Sometimes combining several coverages within one evaluation step is required, for
example, when mask overlaying is performed: both target image and mask constitute
To this end,
for loops can be nested. The semantics is straightforward:
each loop visits the coverages listed in turn, hence every combination (actually the
cross product of all coverage sets) is inspected.
Example: "the number of vegetation pixels in Landsat scenes
s3 within the region marked by mask
for s in ( s1, s2, s3 ), r in ( r ) return count( ((s.0-s.1)/(s.0+s.1) > 0.6) * m )
The result consists of three integer numbers indicating the degree of vegetation.
See manual: coverageListExpr