ExtractMapGraph(string osm_pbf_filename)
{
var recreationalVechicleRoadTags = new HashSet<string>(
new[] {
// https://wiki.openstreetmap.org/wiki/Key:highway
"motorway",
"trunk",
"primary",
"secondary",
"tertiary",
"unclassified",
"residential",
"service",
// ramps and other road connectors
"motorway_link",
"trunk_link",
"primary_link",
"secondary_link",
"tertiary_link",
}
);
var onewayIdentifiers = new HashSet<string>(new [] { "yes", "1", "true" });
var nodes = new Dictionary<long, FindingDirectionsState>();
// TODO: figure out why hashset of OSM edge is fine but IWeightedGraphEdge fails to dedupe
var edges = new HashSet<OsmEdge>();
var graphNodes = new HashSet<FindingDirectionsState>();
using(var fileStream = File.OpenRead(osm_pbf_filename))
using(var source = new PBFOsmStreamSource(fileStream))
foreach (var element in source)
{
switch(element.Type)
{
case OsmGeoType.Node:
if (!element.Id.HasValue) continue;
var osm_node = (Node)element;
if (!osm_node.Latitude.HasValue || !osm_node.Longitude.HasValue) continue;
var graph_node = new FindingDirectionsState(
nodeId: (ulong)osm_node.Id.Value,
latitude: osm_node.Latitude.Value,
longitude: osm_node.Longitude.Value
);
nodes[element.Id.Value] = graph_node;
break;
case OsmGeoType.Way:
if (!element.Tags.ContainsKey("highway")) continue;
var highwayType = element.Tags.GetValue("highway");
if (!recreationalVechicleRoadTags.Contains(highwayType)) continue;
var way = (Way)element;
if (way.Nodes.Length < 2) continue;
bool isOneWay = element.Tags.ContainsKey("oneway") && onewayIdentifiers.Contains(element.Tags["oneway"]);
for(int i = 1; i < way.Nodes.Length; i++)
{
var a = nodes[way.Nodes[i-1]];
var b = nodes[way.Nodes[i]];
graphNodes.Add(a);
graphNodes.Add(b);
var distance = DistanceHelper.Haversine(a.Latitude, a.Longitude, b.Latitude, b.Longitude);
edges.Add(new OsmEdge(a, b, distance));
if (!isOneWay) edges.Add(new OsmEdge(b, a, distance));
}
break;
case OsmGeoType.Relation:
// don't need these?
break;
}
}
var graph = new AdjacencyListWeightedGraph<FindingDirectionsState, double>(edges);
return (graph, graphNodes);
}
public static Func <FindingDirectionsState, double> MakeStraightLineDistanceHeuristic(FindingDirectionsState goal)
{
return(from => DistanceHelper.Haversine(from.Latitude, from.Longitude, goal.Latitude, goal.Longitude));
}
public override double DistanceSquaredBetweenPoints(double[] a, double[] b)
{
double dst = DistanceHelper.Haversine(a[0], a[1], b[0], b[1]);
return (float)(dst * dst);
}