dodgr_contract_graph

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

Distances on dual-weighted directed graphs using
priority-queue shortest paths (Padgham (2019) <doi:10.32866/6945>).
Weighted directed graphs have weights from A to B which may differ
from those from B to A. Dual-weighted directed graphs have two sets
of such weights. A canonical example is a street network to be used
for routing in which routes are calculated by weighting distances
according to the type of way and mode of transport, yet lengths of
routes must be calculated from direct distances.

Mark Padgham

dodgr

Distances on Directed Graphs

Andreas Petutschnig

David Cooley

Robin Lovelace

Andrew Smith

Malcolm Morgan

Andrea Gilardi

Shane Saunders

Stanislaw Adaszewski

dodgr_contract_graph function

<dl><dt>graph</dt>
<dd>A flat table of graph edges. Must contain columns labelled
<code>from</code> and <code>to</code>, or <code>start</code> and <code>stop</code>. May also contain
similarly labelled columns of spatial coordinates (for example
<code>from_x</code>) or <code>stop_lon</code>).</dd>
<dt>verts</dt>
<dd>Optional list of vertices to be retained as routing points.
These must match the <code>from</code> and <code>to</code> columns of <code>graph</code>.</dd>
<dt>nocache</dt>
<dd>If <code>FALSE</code> (default), load cached version of contracted graph
if previously calculated and cached. If <code>TRUE</code>, then re-contract graph even
if previously calculated version has been stored in cache.</dd></dl>

Arguments

Contract graph to junction vertices only. — dodgr_contract_graph

<dl>

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


<dt>verts</dt>
<dd>Optional list of vertices to be retained as routing points.
These must match the <code>from</code> and <code>to</code> columns of <code>graph</code>.</dd>


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

</dl>

Contract graph to junction vertices only.

dodgr_contract_graph: Contract graph to junction vertices only.

Description

Usage

Value

Arguments

See Also

Examples