Removes redundant (straight-line) vertices from graph, leaving only junction
vertices.
Usage
dodgr_contract_graph(graph, verts = NULL)
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.
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).