I am searching for the kernel function the ArcGIS tool "Kernel Density" is using. The ArcGIS help mentions the following: "The kernel function is based on the quadratic kernel function described in Silverman (1986, p. 76, equation 4.5)." I have access to the 1998 print of this book where I can find the equation on the very same page. However, when implementing the kernel, I get rather different results from the Gaussian variant, for example. Can therefore anybody tell me the correct kernel function ArcGIS is using? I think it has to be modified to integrate to 1 or something like that.
I remember this question to be answered in the old ESRI forums and I think that I even have the link to it:
http://forums.esri.com/Thread.asp?c=93&f=995&t=98735
Sadly, the link does not work anymore. (Is there a way to access the old forums?)
Thank you very much in advance.