ABSTRACT
This chapter reviews what has been covered in the literature in acknowledging, evaluating and measuring the effects of generalisation. It starts by analysing all the known sources of map error and comparing these with the errors introduced by generalisation. During the map-making process there are a number of opportunities for the introduction of errors. In describing generalisation effects, one of the most useful distinctions is between generalisation for analysis purposes and generalisation for display purposes - termed, by Brassel and Weibel, statistical and cartographic generalisation. The term 'statistical generalisation' has led at times to misconceptions and, recently, the equivalent term model generalisation has been introduced instead. Model generalisation is mainly a filtering process. Positional accuracy determines how closely the position of discrete objects shown on a map or in a spatial database agree with their position on the ground.
