Well now you sort of can!
I just presented at AMIA on my methodology to use limited patient demographic/location data to estimate the number of patient cases at a smaller geographic locality. The methodology is split between a Monte Carlo simulation and GIS methods (Semi-variogram+Kriged Surface+Geographical Gaussian Simulation) to estimate patient cases. Currently the monte carlo part is already coded and freely available on my
bitbucket. The latter half of the code is coming as soon as we can identify an appropriate open source GIS library to port it the current code into.