Questions about pathdistGen() and ipdwInterp() about ipdw HOT 2 CLOSED

I'm happy you're finding this code to be useful. It's been some years since I was seriously using this code myself so here's my best guess/recollection.

1. I recommend setting ipdw_range to a multiple of the distance among observation points. In the vignette I set it to 10x this value but I think it depends on what kind of spatial density you have in your observations. Try a few and see how it looks (you could also try a few in a leave-one-out cross validation scheme). I chose the second break for ipdw_dist because the first would be 0. Do you see a need to have this be set by the user instead of hard-coded?
2. I think this was ported from the reference code in Suominen et al. 2010 and I believe it's to enforce realistic spatial decay in a simple way without being overly complicated.
3. I don't recall this being an issue. My initial guess is that it's a spatial duplicate with one of your other points or that its distance with another point is smaller that the resolution of your raster inputs/outputs/intermediates.

P.S. I don't know if you're a Python user but even if you're not it might be a good idea to take a look at the following Python implementation in case it's useful to read through:
https://github.com/wrightky/ipdw

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Thanks for the responses! I am just returning from vacation today, but will take a closer look this week and then close the comment.

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