Reporting at 1 square km grid, which may be useful in showing small areas of geographic association with environmental risk. However, it has the negative effect of highlighting certain areas as high risk which have a low population density. (eg. if one square has only one family, and half of the family got infected, then the square will show up as a high incidence.) This problem can be overcome either by considering only those squares containing a minimum number of people or by aggregating data for a number of years.
Malaria Case Incidence per square kilometre in Ingwavuma and Ubombo, 1994