# Calculating density using information linked to polygons?

I'm fairly new at GIS and am using ArcMap to calculate the population density of lizards on an island. On our island, we have about 80 trees, and each tree is mapped as a polygon on a single layer. We have a database of several thousand lizards that we have captured on these trees (and noted capture location). Our goal is to add the lizards to the map to calculate density across the island. Right now, we have attributes for each tree that are #males, #females, #total, which we hoped would give use the ability to calculate both density and sex ratio.

Can we use these attributes to calculate density of specific areas with a given kernel size? Based on what I've read, it seems like you might only be able to calculate density of lines and points.

• Put n random lizards inside polygon and proceed points approach – FelixIP Oct 31 '16 at 3:49
• Sounds like you have been sampling trees only. If you run some point density raster tool that will predict lizards not on trees,is that your intention? I'm no statistician but why not calculate density for each tree, a simple calculation of number by area? So you are mapping density at a tree level rather than predicting density over the whole island and in areas you have not sampled? – Hornbydd Oct 31 '16 at 8:58
• We can't really calculate density per tree because the trees are somewhat overlapping. There are some areas where that would be easy, but some areas have several trees that might fit into the kernel size that we want, so we'd have to make all of the overlapping polygons and calculate each of them by hand. – Ariel Kahrl Oct 31 '16 at 15:07
• If you have overlapping polygons have a look at the union tool to resolve that. – Hornbydd Oct 31 '16 at 23:15