upstream

upstream

Sum of the cell values of its first upstream cell(s)

Result = upstream(ldd, material)

ldd

spatial ldd

material

spatial, non spatial scalar

Result

spatial scalar

Operation

For each cell the neighbour cells that have a local drain direction on ldd towards the cell are determined. These are cells that drain directly to the cell. On Result the cell is assigned the sum of the material values of these first upstream cells. This is done for each cell.

Notes

A cell with a missing value on ldd or material is assigned a missing value on Result. Additionally the downstream neighbour of a missing value cell on material is assigned a missing value on Result.

Group

This operation belongs to the group of Neighbourhood operators; local drain directions

Examples

1. • pcrcalc

   binding

   Result = Result.map;

   Ldd = Ldd.map;

   Expr = Expr.map;

   initial

   report Result = upstream(Ldd, Expr);

   
   

   • python

   Ldd = readmap(“Ldd.map”)

   Expr = readmap(“Expr.map”)

   Result = upstream(Ldd, Expr)

   Result.map	Ldd.map	Expr.map