#Route calculations using Neo4j graph database over OSM data
The goal of the project is to prove that Neo4j can be successfully used as a route calculation engine for OSM data.
##Problem
Talking about route calculation we want to think in terms of roads (OSM Way ) and road junctions (OSM Node ) .
However OSM Nodes represents road shape points and does not always corresponds to real-world road junctions.
This leads to the situation when resulting road graph is overloaded with redundant nodes and relations.
##Implementation
####OSM Data Loading
OsmImporter class is responsible for loading of OSM nodes and only those ways that are marked as 'highway' with
respect to ONEWAY/BIDERECTIONAL attribution.
###Graph Optimization
OsmRoutingOptimizer does the following:
- removes nodes and corresponding relations that doesn't model real-world road junctions or start\end point of a road
- creates new relations between survived nodes
- each new relation will receive :
- WAY_DISTANCE attribute that will hold relation's distance in meters value
- WAY_GEOMETRY attribute that will contain WKT representation of road geometry(merged\removed nodes will go there). E.g.
LINESTRING (103.9740925 13.3479685, 103.9741521 13.3459453, 103.9741086 13.3455537)
####Route Calculation And Test
RouteCalculator can be used to calculate route between two nodes :
List<LineString> route = new RouteCalculator().findRoute(getStartNode(db), getEndNode(db));
Calculated route could be visualized using KML and Google Earth application.
Route calculated somewhere in Siem Reap :)
