This talk first touched on why we use maps at all then look at the factors (“covariates”) that drive disease occurrence. The session led by William Wint (E.R.G.O., UK) & Cederic Marsboom (Avia-GIS, Belgium) examines what these covariates might be and identify the environmental, agricultural, socio-economic, ecological and climatic parameters that can best contribute to spatial modelling. It is also important to know where these data can be found, what are the pros and cons of different data sources for the common covariate variables, and what datasets can be used for different types of models. The available covariate data are not always in a form that is convenient for spatial modellers and the session will provide examples of the processing and selection needed to provide modellers with what they need. Finally, the use of selected covariates in spatial models is be discussed and illustrated with worked examples.