org.opentripplanner.graph_builder.module.osm

Class WalkableAreaBuilder

java.lang.Object

org.opentripplanner.graph_builder.module.osm.WalkableAreaBuilder

public class WalkableAreaBuilder
extends Object

Theoretically, it is not correct to build the visibility graph on the joined polygon of areas with different levels of bike safety. That's because in the optimal path, you might end up changing direction at area boundaries. The problem is known as "weighted planar subdivisions", and the best known algorithm is O(N^3). That's not much worse than general visibility graph construction, but it would have to be done at runtime to account for the differences in bike safety preferences. Ted Chiang's "Story Of Your Life" describes how a very similar problem in optics gives rise to Snell's Law. It is the second-best story about a law of physics that I know of (Chiang's "Exhalation" is the first).

Anyway, since we're not going to run an O(N^3) algorithm at runtime just to give people who don't understand Snell's Law weird paths that they can complain about, this should be just fine.

Constructor Summary

Constructors

Constructor and Description
WalkableAreaBuilder(Graph graph, OSMDatabase osmdb, WayPropertySet wayPropertySet, StreetEdgeFactory edgeFactory, OpenStreetMapModule.Handler handler)

Method Summary

Modifier and Type	Method and Description
void	buildWithoutVisibility(org.opentripplanner.graph_builder.module.osm.AreaGroup group) For all areas just use outermost rings as edges so that areas can be routable without visibility calculations
void	buildWithVisibility(org.opentripplanner.graph_builder.module.osm.AreaGroup group, boolean platformEntriesLinking)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

WalkableAreaBuilder

public WalkableAreaBuilder(Graph graph,
                           OSMDatabase osmdb,
                           WayPropertySet wayPropertySet,
                           StreetEdgeFactory edgeFactory,
                           OpenStreetMapModule.Handler handler)

Method Detail

buildWithoutVisibility

public void buildWithoutVisibility(org.opentripplanner.graph_builder.module.osm.AreaGroup group)

For all areas just use outermost rings as edges so that areas can be routable without visibility calculations

Parameters:

group -

buildWithVisibility

public void buildWithVisibility(org.opentripplanner.graph_builder.module.osm.AreaGroup group,
                                boolean platformEntriesLinking)