ABSTRACT

Chapter 1 introduced the idea that information system development follows a sequence of stages, beginning with high-level conceptual models through to low-level computational models and implementation. The different emphasis at each stage of the development process helps to ensure that the resulting systems are both easy to understand and computationally efficient (see section 1.3.4). In the previous chapter, the focus was on high-level conceptual models. The chapter paid special attention to the human views of applications that feature geospatial information. In this chapter we start to consider questions that are closer to low-level computational processing. Specifically, this chapter is concerned with the representation of geospatial data in a GIS, and how various spatial operations are performed on this data.