The functionality of road
weighting has been altered through a patch application. If using a weighted
roads data base please see a desription
In any region some transportation lines may have
more affect upon urbanization than others. Through road weighting this
type of influence may be incorporated into the model.
How road weighting works:
Road weighting does not affect a road pixel's likelihood of being found
during a road search (see: equation 4.1 of road
influenced growth, and road_gravity_coefficient).
All road pixels have an equal probability to influence urban development.
Instead, the weighting affects how the new urban center may be dispersed
along the road network during the random walk (see: equation 4.2
of road influenced growth, and dispersion_coefficient).
The highest road weight will allow a maximum distance, or number of steps,
for the new urban center to travel along the road. A lower weight will
cause some porportion of this maximum distance to be traveled. In this
way smaller roads will have a more local affect, while larger roads may
allow urbanization to occur further away along the network.
- Applied value is derived from the road pixel
run_value = (roads(i, j) / max_road_value * dispersion_coefficient)
where run_value is the maximum number of steps
traveled along the road network by an urban pixel. The value of a
road pixel at a given location is described by road(i,j). Max_road_value
is defined as 100. Run_value is at a maximum of 100 when (road(i,j)
== max_road_value) and (dispersion_coefficient == 100).