i don’t see why this has to be the case. i don’t know how they decided on their threshold, but i would just assume they compared the geomodel results against known ranges and derived a best fit threshold that way (or something like that).
it looks like this thread is an extension of the San Jacinto Mountain thread. based on the discussion there, it seems like you’re trying figure out how the model works so that you can help troubleshoot it.
at the risk of being characterized again as a discourager of learning and squasher of dreams, i would just say that adequately troubleshooting stuff like this often is not possible without having access to the setup that produced the unexpected results. for example, in the other thread, it was noted that the developers found something potentially wrong with the “elevation encoding”. to me, that sounds like the sort of thing that no amount of reading papers or providing Goldilocks explanations is going to surface. it sounds like the sort of thing – maybe an actual bug in the code or problem in the elevation inputs – that you will only see if your run stuff and compare the results against manually calculated or manually determined results and then trace things backward in the processing to see when the problem first pops up. it looks like the participants in the other thread already got as far as they could reasonably expect to get in helping to troubleshoot things by identifying unusual cases.