Calculate matrix of pair-wise travel times between points.

dodgr_times(graph, from = NULL, to = NULL, shortest = FALSE, heap = "BHeap")

## Arguments

graph A dodgr network returned from the weight_streetnet function using a network obtained with the osmdata osmdata_sc function, possibly contracted with dodgr_contract_graph. Vector or matrix of points from which route distances are to be calculated (see Notes) Vector or matrix of points to which route distances are to be calculated (see Notes) If TRUE, calculate times along the shortest rather than fastest paths. 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

square matrix of distances between nodes

## Examples

# A simple graph
graph <- data.frame (from = c ("A", "B", "B", "B", "C", "C", "D", "D"),
to = c ("B", "A", "C", "D", "B", "D", "C", "A"),
d = c (1, 2, 1, 3, 2, 1, 2, 1))
dodgr_dists (graph)
#>   A B C D
#> A 0 1 2 3
#> B 2 0 1 2
#> C 2 2 0 1
#> D 1 2 2 0
# A larger example from the included [hampi()] data.
graph <- weight_streetnet (hampi)
from <- sample (graph$from_id, size = 100) to <- sample (graph$to_id, size = 50)
d <- dodgr_dists (graph, from = from, to = to)
# d is a 100-by-50 matrix of distances between from and to

if (FALSE) {
# a more complex street network example, thanks to @chrijo; see
# https://github.com/ATFutures/dodgr/issues/47

xy <- rbind (c (7.005994, 51.45774), # limbeckerplatz 1 essen germany
c (7.012874, 51.45041)) # hauptbahnhof essen germany
xy <- data.frame (lon = xy [, 1], lat = xy [, 2])
essen <- dodgr_streetnet (pts = xy, expand = 0.2, quiet = FALSE)
graph <- weight_streetnet (essen, wt_profile = "foot")
d <- dodgr_dists (graph, from = xy, to = xy)
# First reason why this does not work is because the graph has multiple,
# disconnected components.
table (graph$component) # reduce to largest connected component, which is always number 1 graph <- graph [which (graph$component == 1), ]
d <- dodgr_dists (graph, from = xy, to = xy)
# should work, but even then note that
table (essen$level) # There are parts of the network on different building levels (because of # shopping malls and the like). These may or may not be connected, so it may # be necessary to filter out particular levels index <- which (! (essen$level == "-1" | essen$level == "1")) # for example library (sf) # needed for following sub-select operation essen <- essen [index, ] graph <- weight_streetnet (essen, wt_profile = "foot") graph <- graph [which (graph$component == 1), ]
d <- dodgr_dists (graph, from = xy, to = xy)
}
`