Chapter 9
Analysis and Process modelling Rolf de By Otto Huisman Menno-Jan Kraak Introduction We know from preceding chapters that the analytical capabilities of a GIS make use of spatial and non-spatial (attribute) data to answer questions and solve problems that are of spatial relevance. We now make a distinction between analysis (or analytical operations) and analytical models (often referred to as “modelling”). And by analysis we actually mean only a subset of what is usually implied by the term: we do not specifically deal with advanced statistical analysis (such as cluster detection or geostatistics), which is beyond the scope of this textbook. All knowledge of the world is based on models of some kind—whether idiosyncratic interpretations, culturally-based stereotypes or complex equations that describe a physical phenomenon. We have already seen in Chapter 7 that there are different types of models and that the word itself has different meanings in different contexts. Section 8.1 notes that even spatial data are themselves a kind of “model” of some part of the real world. Here, in this chapter, we focus on analytical functions that form the building blocks for application models. Section 9.1 presents a framework that defines four main classes of these functions. Each class is then discussed, with the help of examples, in detail in subsequent sections. The aim is to make clear to the reader that these operations can be combined in various ways to perform increasingly complex analyses.
9.1
Classification of analytical GIS capabilities
There are many ways to classify the analytical functions of a GIS. The classification presented here is essentially the one put forward by Aronoff [4], which makes the following distinctions:
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