Habitat Risk Assessment (HRA) model issue
I have a question about using files containing multiple polylines as stressor layers. I am using the Habitat Risk Assessment model to evaluate the potential impacts of shipping on whale populations. My stressor data are aggregations of ship track polylines that are divided into three separate shp files by ship type (i.e., bulk carriers, cargo, tanker).
The problem arises when the model calculates cumulative risk in the whale habitat. I believe it is only accounting for the overlap in stressor layers rather than the intensity of polylines within a layer. For example, if my tanker shp file demonstrates that 100 tankers passed through the exact same area, the HRA model gives that the same weight as any area where only one tanker passed. The additional risk would only be accounted for if, say, a bulk carrier and a tanker passed through the same area (i.e., two overlapping stressors).
The only solution that I can think of is to create separate shp files for each ship track polyline. However, given that I have hundreds of ships, this is infeasible. Does anyone have any suggestions for ways to incorporate the spatial variation in the intensity of shipping within the HRA model?