dodgr_contract_graph {dodgr}

Contract graph to junction vertices only.

Description

Removes redundant (straight-line) vertices from graph, leaving only junction vertices.

Usage

dodgr_contract_graph(graph, verts = NULL, nocache = FALSE)

Arguments

graph

A flat table of graph edges. Must contain columns labelled from and to, or start and stop. May also contain similarly labelled columns of spatial coordinates (for example from_x) or stop_lon).

verts

Optional list of vertices to be retained as routing points. These must match the from and to columns of graph.

nocache

If FALSE (default), load cached version of contracted graph if previously calculated and cached. If TRUE, then re-contract graph even if previously calculated version has been stored in cache.

Value

A contracted version of the original graph, containing the same number of columns, but with each row representing an edge between two junction vertices (or between the submitted verts, which may or may not be junctions).

See Also

Other modification: dodgr_components(), dodgr_uncontract_graph()

Examples

graph <- weight_streetnet (hampi)
nrow (graph) # 5,973
graph <- dodgr_contract_graph (graph)
nrow (graph) # 662