OCNet (version 0.4.0)

paths_OCN: Calculate paths between nodes in an Optimal Channel Network

Description

Function that determines upstream and downstream paths and path lengths between any nodes of the network at the aggregated level.

Usage

paths_OCN(OCN, pathsRN = FALSE, includeDownstreamNode = FALSE)

Arguments

OCN

List as produced by aggregate_OCN.

pathsRN

Logical. If TRUE paths and path lengths at the RN level are copied to the output list. If FALSE, only path lengths at the RN level are copied to the output list.

includeDownstreamNode

Logical. If TRUE, path lengths include the length of the edge departing from the last downstream node of the path.

Value

A list that contains all objects contained in OCN, in addition to the objects listed below.

RN$downstreamPath

(only present if pathsRN = TRUE) List (of length OCN$RN$nNodes) whose object i is a list (of length OCN$RN$nNodes). If nodes i and j are connected by a downstream path, then RN$downstreamPath[[i]][[j]] is a vector containing the indices of the nodes constituting such path (i and j are included). If i and j are not connected by a downstream path, then RN$downstreamPath[[i]][[j]] = 0.

RN$downstreamPathLength

Sparse matrix (OCN$RN$nNodes by OCN$RN$nNodes) containing length of paths between nodes that are connected by a downstream path; if i and j are not connected by a downstream path, then RN$downstreamPathLength[i,j] = 0. Note that RN$downstreamPathLength[i,i] = 0 if includeDownstreamNode = FALSE; alternatively, it is RN$downstreamPathLength[i,i] = OCN$RN$leng[i]. It is a spam object.

AG$downstreamPath

List (of length OCN$AG$nNodes) whose object i is a list (of length OCN$AG$nNodes). If nodes i and j are connected by a downstream path, then AG$downstreamPath[[i]][[j]] is a vector containing the indices of the nodes constituting such path (i and j are included). If i and j are not connected by a downstream path, then AG$downstreamPath[[i]][[j]] = 0.

AG$downstreamPathLength

Sparse matrix (OCN$AG$nNodes by OCN$AG$nNodes) containing length of paths between nodes that are connected by a downstream path; if i and j are not connected by a downstream path, then AG$downstreamPathLength[i,j] = 0. Note that AG$downstreamPathLength[i,i] = 0 if includeDownstreamNode = FALSE; alternatively, it is AG$downstreamPathLength[i,i] = OCN$AG$leng[i]. It is a spam object.

AG$downstreamLengthUnconnected

Sparse matrix (OCN$AG$nNodes by OCN$AG$nNodes). AG$downstreamLengthUnconnected[i,j] is the length of the downstream portion of a path joining node i to j if i and j are not connected by a downstream path. Specifically, AG$downstreamLengthUnconnected[i,j] = AG$downstreamPathLength[i,k], where k is a node such that there exist a downstream path from i to k and from j to k, and these paths are the shortest possible. Note that the length of the upstream portion of the path joining i to j is given by AG$downstreamLengthUnconnected[j,i]. If instead i and j are joined by a downstream path, then AG$downstreamLengthUnconnected[i,j] = 0. It is a spam object.

Examples

# NOT RUN {
# 1) Calculate paths between nodes of an OCN
OCN <- paths_OCN(aggregate_OCN(landscape_OCN(OCN_20), thrA = 4))
# }
# NOT RUN {
# 2) Display distance to outlet (at the RN level) along the main stem
# of an OCN
OCN <- aggregate_OCN(landscape_OCN(OCN_250_T)) # this takes some seconds
OCN <- paths_OCN(OCN, pathsRN = TRUE) # this takes some seconds

distanceToOutlet <- OCN$RN$downstreamPathLength[,OCN$RN$outlet]
farthestNode <- which(distanceToOutlet == max(distanceToOutlet))
mainStem <- OCN$RN$downstreamPath[[farthestNode]][[OCN$RN$outlet]]
theme <- rep(NaN, OCN$RN$nNodes)
theme[mainStem] <- distanceToOutlet[mainStem]

draw_thematic_OCN(theme, OCN)
title("Distance to outlet along the main stem [pixel units]")
# }