Timeline for What does it mean to "renormalize" the density of a kernel distribution?
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
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| Nov 20, 2019 at 12:34 | vote | accept | spops | ||
| Nov 19, 2019 at 18:03 | comment | added | carlo | I don't know any package for doing that, but if it is a raster I think it would be very easy to do by hand (I mean by coding it, the integral would be evaluated as a sum over rester points). I never did it though, so I don't really know your workflow, sorry. | |
| Nov 19, 2019 at 16:53 | comment | added | spops | Let's say I or another future poster wanted to actually go about actually doing this - is renormalizing the kernel raster something typically done by stats packages (e.g. in R)? I'm assuming dividing by the integral isn't something done longhand anymore? | |
| Nov 19, 2019 at 16:46 | comment | added | spops | Thanks whuber & carlo for the clear explanations. I've been looking for the best method to estimate home ranges/density and have gotten the impression that cutting the land out is a bad idea - but I think I will post a separate question on this topic in the GIS forum! | |
| Nov 19, 2019 at 16:39 | comment | added | carlo | @spops I didn't really understand your comment. What do you mean? | |
| Nov 19, 2019 at 16:36 | comment | added | whuber♦ | +1. But note that it's likely that in this case the KDE does not estimate a probability: it will estimate the number of sharks per unit surface area of ocean. Your argument applies, mutatis mutandis: normalization means the total number of estimated sharks equals the total number of observed sharks. spops: there's no bell curve imposed. Normalization will not change a colored contour map of your density at all, for instance--it leaves the spatial pattern (within the water areas) unchanged. Normalization is a poor idea when many of the sharks are close to land: it downweights them. | |
| Nov 19, 2019 at 16:36 | comment | added | spops | So essentially this is forcing a normal distribution ("bell curve") on all points in both dimensions of a 2D kernel? (This is the struggle of ecology grad students only knowing rudimentary statistics) | |
| Nov 19, 2019 at 16:23 | history | answered | carlo | CC BY-SA 4.0 |