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

CHAPTER 5: TIME IN HISTORICAL GIS

5.2 The need for understanding through space and time

Researchers have long argued that to truly understand the world, one must understand change through both time and space. This was the argument underlying Langton's article where he claims that rather than simply comparing isolated snapshots that are assumed to be in equilibrium (termed synchronic analysis), researchers should be able to study how processes operate through time "cutting across a successive series of synchronic pictures of the system" (Langton 1972, 137). He terms this diachronic analysis. More recently Massey presents a strong argument for the need among geographers for a full understanding of space-time (Massey 1999). She argues that we need to be able to understand time to tell the story of how an individual place developed, and to understand space to understand the complexity of the way different places develop. Only by having multiple routes through space and time can the full complexity of the world be understood. Unfortunately, the complexity of handling data's three components simultaneously has led to researchers usually either simplifying space to preserve temporal detail, or simplifying time to preserve spatial detail. Cliff and Haggett summarise this by saying "If we are to preserve a consistent time series, we need to sacrifice (through amalgamation) a great deal of temporal detail. Conversely, if we wish to retain the maximum amount of spatial detail then we can only have short and broken time series" (Cliff and Haggett 1996, 332).

Researchers using GIS in a historical context have also argued for the need to understand the temporal as well as the spatial. Healey and Stamp argue that to understand regional economic development fully, the researcher must be able to disaggregate through both space and time as much as possible (Healey and Stamp 2000). This, they argue, involves looking at thousands of individual firms, preferably on a monthly basis over an extended period of time. Doing this requires being able to incorporate the rapidly changing locations of the firms and also developments in the transport network and changes in land ownership. MacDonald and Black researching the history of the book and print culture, come to broadly similar conclusions (MacDonald and Black 2000). They argue that a spatial and temporal framework is needed because to understand the development of print culture over time one must understand the complex relationships between such diverse activities as migration and other socio-economic variables (especially literacy rates), information about people employed in the book trade (location, occupation, and gender), the growth of libraries (location, type, and size), newspaper circulations, and so on, as they develop over time.