Spatial stratified heterogeneity (SSH), referring to the within strata are more similar than the between strata, a model with global parameters would be confounded if input data is SSH. Note that the "spatial" here can be either geospatial or the space in mathematical meaning. Geographical detector is a novel tool to investigate SSH: (1) measure and find SSH of a variable Y; (2) test the power of determinant X of a dependent variable Y according to the consistency between their spatial distributions; and (3) investigate the interaction between two explanatory variables X1 and X2 to a dependent variable Y.
To install the stable version from CRAN:
install.packages('geodetector')Wang JF, Li XH, Christakos G, Liao YL, Zhang T, Gu X & Zheng XY. 2010.Geographical detectors-based health risk assessment and its application in the neural tube defects study of the Heshun region, China. International Journal of Geographical Information Science 24(1): 107-127.
Wang JF, Zhang TL, Fu BJ. 2016.A measure of spatial stratified heterogeneity. Ecological Indicators 67(2016): 250-256.