topologies: Build topologies Build pixel and reach topologies for...

In flee-group/watershed: Tools for Watershed Delineation

Build topologies Build pixel and reach topologies for delineated streams

Description

Build topologies Build pixel and reach topologies for delineated streams

Usage

pixel_topology(x, drainage, stream, id)

reach_topology(x, Tp)

Arguments

x	A raster::stack, such as one created by delineate(), or specify layers separately with drain and stream.
drainage	Optional, ignored if x is provided; a drainage direction raster
stream	Optional, ignored if x is provided; a delineated stream raster, all non-stream cells must be NA
id	Optional, ignored if x is provided; a raster of pixel ids, as, stream
Tp	Topology for pixels in the network, e.g., the output from pixel_topology().

Details

The topology is a square matrix showing immediate adjacency between pixels/reaches. Each row/column in the topology is a single pixel/reach. Zero entries indicate no adjacency between two nodes. A non-zero entry for row i column j indicates that i is upstream of j. The value in the entry is the reaction length of the upstream pixel/reach; this is the midpoint to midpoint distance from i to j. The actual length of each node is stored in the length attribute; thus Tp[i,j] == sum(attr(Tp, "length")[c(i,j)])/2

Value

A Matrix::sparseMatrix giving the pixel or reach topology

Examples

    data(kamp_dem)
    kamp = delineate(kamp_dem, outlet = NA)
    Tp = pixel_topology(kamp)
    Tr = reach_topology(kamp, Tp)

flee-group/watershed documentation built on July 25, 2022, 12:46 p.m.