A place in history: a guide to using GIS in historical research

CHAPTER 5: TIME IN HISTORICAL GIS

5.3 Time in GIS

Peuquet (1994) argues that a fully temporal GIS would be able to answer three types of queries:

1. Changes to an object such as 'has the object moved in the last two years?', 'where was the object two years ago?' or 'how has the object changed over the past five years?'
2. Changes in the object's spatial distribution such as 'what areas of agricultural land-use in 1/1/1980 had changed to urban by 31/12/1989?', 'did any land-use changes occur in this drainage basin between 1/1/1980 and 31/12/1989?', and 'what was the distribution of commercial land-use 15 years ago?'
3. Changes in the temporal relationships among multiple geographical phenomena such as 'which areas experienced a landslide within one week of a major storm event?', 'which areas lying within half a mile of the new bypass have changed from agricultural land use since the bypass was completed?'
   

Unfortunately, the layer-based data model used by GIS does not allow easy handling of queries of this type and relatively little progress has been made in this direction. The basic problem relates to topology. GIS handles space efficiently by incorporating spatial topology (see Chapter 2). To also handle time efficiently it would need to have spatio-temporal topology. Although some suggestions have been put forward for doing this, mainly based on object-oriented technology (see, for example, Egenhofer and Golledge 1998; Wachowicz 1999), these have not yet been incorporated into GIS software.