ABSTRACT
In the previous chapter the locational component of geographic objects or features was discussed. This chapter will deal with the attribute component. Attributes can answer questions like: What does one find at a specific location and what are its characteristics? The map type that visualizes these attribute data is the thematic map, and its design is discussed in this chapter. Attribute data can be qualitative (language, soil characteristics, geological formations) or quantitative (air pressure, height above sea level, income or election results) – see Figure 7.1. The attributes can change and the objects that have these attributes can change; visualization of these changes is dealt with in Chapter 8. For rendering attribute data one needs a topographic background: it is no use presenting a geological map if one cannot locate the geological formation one is interested in. Attribute data are usually collected from aerospace imagery, during fieldwork or statistical surveys.
