dodgr_isodists: dodgr_isodists

Description Usage Arguments Value Note Examples

Description

Calculate isodistance contours from specified points. Function is fully vectorized to calculate accept vectors of central points and vectors defining multiple isodistances.

Usage

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dodgr_isodists(graph, from = NULL, dlim = NULL, heap = "BHeap")

Arguments

graph

data.frame or equivalent object representing the network graph (see Notes)

from

Vector or matrix of points from which isodistances are to be calculated.

dlim

Vector of desired limits of isodistances in metres.

heap

Type of heap to use in priority queue. Options include Fibonacci Heap (default; FHeap), Binary Heap (BHeap), Trinomial Heap (TriHeap), Extended Trinomial Heap (TriHeapExt, and 2-3 Heap (Heap23).

Value

A single data.frame of isodistances as points sorted anticlockwise around each origin (from) point, with columns denoting the from points and dlim value(s). The isodistance contours are given as id values and associated coordinates of the series of points from each from point at the specified isodistances.

Note

Isodists are calculated by default using parallel computation with the maximal number of available cores or threads. This number can be reduced by specifying a value via RcppParallel::setThreadOptions (numThreads = <desired_number>).

Examples

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graph <- weight_streetnet (hampi)
from <- sample (graph$from_id, size = 100)
dlim <- c (1, 2, 5, 10, 20) * 100
d <- dodgr_isodists (graph, from = from, dlim)

dodgr documentation built on Aug. 8, 2021, 1:06 a.m.