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MFworks Tutorial – 03 Incremental Linkage

Posted on 2007-11-12 by

Revised on: 2015-10-02

This operation infers the lineal characteristic of raster cells, by equating consecutive locations with a set of straight lines between them (Figure 1-3). Based on its relations with neighboring cells that have the same attribute value, each cell is given a linkage value indicating how it is linked to other cells.

Incremental Linkage, cell value infers the linear structure it represents.
© Thinkspace

By assigning a value to each cell equivalent to the linear feature it represents it is possible to create a network similar to a road network. The smaller the cell resolution, the better the real-world road network will be approximated by this procedure.

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Posted in mfworks
Tags: flow direction, incremental linkage, mfworks, network

MFworks Tutorial – 04 Directional Identifier

Posted on 2007-11-12 by

Revised on: 2015-10-02

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,

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Posted in mfworks
Tags: directional identifier, flow direction, incremental linkage, mfworks

MFworks Tutorial – 05 Cost surface

Posted on 2007-11-12 by

Revised on: 2015-10-02

Usually, to generate a cost-of passage surface, several variables will be collapsed into one layer. These variables might be road class, average speed, traffic density, and congestion during specific time of day or other factors that contribute to the overall cost variable. The cost-of-passage surface can be defined by a variety of measurement units: time, fuel consumption, money or other possible cost units, for which the least cost passage is to be determined.

Using average speed and time as a means of inferring cost-of-passage is among the most common approach in network analysis, since it is easy to use and calculate. However, “least cost” does not always need to be “least time”; it may just as well be least fuel,

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