downstream

downstream

Cell gets value of the neighbouring downstream cell

Result = downstream(ldd, expression)
expression
spatial boolean, nominal, ordinal, scalar, directional, ldd
ldd
spatial ldd
Result
spatial type of expression

Operation

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.

Notes

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.

Group

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

See Also

lddmask

Examples

  1. • pcrcalc
    binding
    Result = Result.map;
    Ldd = Ldd.map;
    Expr = Expr.map;
    initial
    report Result = downstream( Ldd, Expr);

    • python
    Ldd = readmap(“Ldd.map”)
    Expr = readmap(“Expr.map”)
    Result = downstream( Ldd, Expr)
    Result.map Ldd.map Expr.map
    _images/downstream_Result.png _images/accu_Ldd.png _images/downstream_Expr.png

Table Of Contents

Previous topic

directional

Next topic

downstreamdist