Hello! I’m a Master’s student looking at applying the Coastal Vulnerability model to a small Caribbean island. After a few tries I have successfully run the model using the latest InVEST 3.8.1. However, I have some questions about the habitat values in the R_Hab column in the final exposure output.
Many of my results are listed as 1 despite different combinations of habitat being present. Is this normal or does it reflect that something is not working correctly when generating this output?
Good question! Thanks for sharing your data. It looks like the model is correctly detecting the habitats and then applying Equation 3 from the User’s Guide. But what’s not mentioned is whenever that equation returns a value less than 1, R_hab is set to 1. That’s because the final exposure equation (eq. 1) demands that R_hab uses the same 1-5 scale as all the other R_ variables.
It looks like that happens for every shore point that has three or more habitats of 1 present. From a theoretical perspective, this might be okay. For example, if a shore point is well-protected by coral, mangrove, & coastal forest (all 1s) then arguably it doesn’t really matter if there is also seagrass or low dune present or not…the point is very well protected by habitats either way. That’s the reasoning behind the equation anyway.