Road Network Data Model Example

To better understand the relationship of the road data file we can work through an illustrative example...

		  destination.csv

		  NODE,ACCOUNT
		  1,destination.MILL

		
		  vertices.csv

		  NODE,X,Y
		  1,430000.0,1410200.0
		  2,430600.0,1410200.0
		  3,431200.0,1410200.0
		  4,434200.0,1410200.0
		  5,434800.0,1410200.0
		  ...
		

5 nodes are defined in this example to create a simple road network. Out of 5 nodes, only Vertex.1 has an account (destination.MILL). Define enough vertices over the planning area to ensure the model has sufficient choice, and that all blocks will have a realistic forwarding distance from an entry point.

		  segments.csv

		  SEGMENT,FNODE,TNODE,LENGTH,MAINTAIN,
		  BUILD,HAUL,DIRECTION
		  0,5,3,214.3,428.75,1286.25,0.017,3
		  1,4,5,23.82521,47.652,0.0,0.0019,3
		  2,4,3,17.46425,34.92,0.0,0.00146,3
		  3,4,2,43.41659,86.838,0.0,0.0036,3
		  4,3,2,37.11992,74.239,0.0,0.0031,3
		  5,2,1,272.125,544.25,1632.75,0.022,3
		  ...
		

In our example, 6 segments attach the vertices. Each segment of road is assigned a length, as well as costs associated with building, maintaining and hauling on that particular section of road. All segments allow bi-directional travel.

		  linkages.csv

		  BLOCK,NODE
		  1,2
		  2,3
		  3,5
		  4,4
		  5,4
		  6,5
		  ...
		

The final step in defining the road network structure is linking individual blocks to starting nodes. In our example, 6 Blocks have been assigned entry points to the road network depending on the closest possible node. At this point the road network data model is complete: vertices, segments, destinations and linkages.