MapGAM is an open-source R package based on work by our group and our collaborators. It creates a map showing estimates of risk by using generalized additive models (GAMs) to smooth over location while adjusting for confounders (Webster et al 2006). Natural applications include mapping of population-based case-control studies (Vieira et al 2005). The software includes permutation tests of the null hypothesis that location is not associated with risk. MapGAM can also be used to "map" risk as a function of a mixture of two exposures.
CRAN site for the MapGAM package
More about spatial epidemiology, how the software works, applications and references
Mixtures: Generalized Concentration Addition
This open-source R code uses Generalized Concentration Addition (GCA) to visualize and test mixtures data (Howard and Webster 2009). It is currently implemented for binary mixtures of full and partial agonists with Hill function dose-response curves where the Hill coefficient is one. It is available for use using a General Public License.
Download R code.
Download test data.
More about chemical mixtures