Result = downstream(ldd, expression)
spatial boolean, nominal, ordinal, scalar, directional, ldd
spatial type of expression
For each cell, assigns to Result the expression value of the neighbouring downstream cell, where downstream cells are determined using the local drain directions on ldd. In case a cell doesn’t have a downstream cell (i.e. a pit) its own expression value is assigned to Result.
A cell with a missing value on ldd and/or expression is assigned a missing value on Result. Its upstream neighbours are assigned a missing value also.
This operation belongs to the group of Neighbourhood operators; local drain directions
- • pcrcalcbindingResult = Result.map;Ldd = Ldd.map;Expr = Expr.map;initialreport Result = downstream( Ldd, Expr);• pythonLdd = readmap(“Ldd.map”)Expr = readmap(“Expr.map”)Result = downstream( Ldd, Expr)