MFworks Tutorial – 04 Directional Identifier

The second step to creating a road network in raster GIS is to impose constraints on the flow that can take place from cell to cell. The value assigned to the centre cell in a 3×3 window indicates the directions the flow can take in and or out of this cell. Figure 1-5 shows how a cell value of 10 is inferred from flow in direction 8 and 2.


Tomlin’s directional identifiers: Cell values indicate possible flow direction in or out of cell

The directional identifiers that are to be assigned to any given cell in a road network can be directly inferred from the Incremental Linkage values, i.e. Incremental Linkage value 28 yields directional constraints value 10, and so on. The transition from Incremental Linkage to Directions is done through a straightforward reassigning of the cell values in the Incremental Linkage map layer to corresponding values in the Directions map layer. More specific constraints, like one-way directions or dead-end roads, which are not directly inferable from the mentioned linkage values, will have to be assigned manually.


Inferring flow directions from Incremental Linkage values in figure above



MFworks – step by step

Posted in mfworks
Tags: , , ,

ARTICLES and PAPERS
Vulnerability and resilience of transport systems
I've been away from academia for the last three years, and in my efforts to catch up with the latest[...]
Adaptation versus Transformation
Many businesses believe themselves to be nested in a stable environment and are confounded when thin[...]
BOOKS and BOOK CHAPTERS
Low Cost Country Sourcing
Low-cost countries. A dream for some and a nightmare for other others. What are typical supply chain[...]
Book review: Transport - Economics and Management
Kept at an executive level, Transport: An Economics and Management Perspective by David A. Hensher a[...]
REPORTS and WHITEPAPERS
Transport infrastructure resilience
Is it possible to devise a simple framework for assessing the resilience of the transport infrastruc[...]
Managing supply chain risk
In September and October 2009 the Economist Intelligence Unit surveyed 500 company executives with r[...]