An accumulator to hold lists of edge changes.
Perform the cost-distance computation.
Perform the cost-distance computation.
The friction layer; pixels are in units of "seconds per meter"
The starting locations from-which to compute the cost of traveling
The maximum cost before pruning a path (in units of "seconds")
This Spark-enabled implementation of the standard cost-distance algorithm mentioned in the "previous work" section of [1] is "heavily inspired" by the MrGeo implementation [2] but does not share any code with it.
1. Tomlin, Dana. "Propagating radial waves of travel cost in a grid." International Journal of Geographical Information Science 24.9 (2010): 1391-1413.
2. https://github.com/ngageoint/mrgeo/blob/0c6ed4a7e66bb0923ec5c570b102862aee9e885e/mrgeo-mapalgebra/mrgeo-mapalgebra-costdistance/src/main/scala/org/mrgeo/mapalgebra/CostDistanceMapOp.scala