First Law of Geography

Tobler's Seminal Article

The main purpose of Tobler's 1970 paper was to simulate the population growth of Detroit from 1910 to 2000 in the form of a computer movie. For every month during the period, Tobler calculated and displayed Detroit's population growth distribution graphically, which then became a single frame in the movie. At 16 frames per second, the simulated changing-population distribution of Detroit over the 20th century could be shown in a movie clip of just over a minute.

The FLG emerged in the context of simplifying the calculation process of population prediction in the Detroit region. In an interview in 1998, Tobler said he used the concept of a law as a means to parse the point he was trying to make. He acknowledged that his conceptualization of a law was influenced by physicist Richard Feynman, who argued that a law is nothing but an educated guess on how nature works, providing that predictions can then be compared with reality. Although Tobler conceded that the first part of the FLG—“Everything is related to everything else”—may not be literally true, he nonetheless defended a law-based approach to geographic research.

FLG and the Foundation of Geographic Information Science

Embedded in FLG are two interwoven theses: the pervasive interrelatedness among all things and how they vary spatially. FLG is also conceptually consistent with the notion of distance decay (also known as the inverse distance effects or distance lapse rate) geographers developed in the mid-20th century.

FLG captures the characteristics of spatial dependence: a defining feature of spatial structures. FLG is normally interpreted as a gradual attenuating effect of distance as we traverse across space, while considering that the effect of distance is constant in all directions. The acceptance of FLG implies either a continuous, smooth, decreasing effect of distance upon the attributes of adjacent or contiguous spatial objects or an incremental variation in values of attributes as we traverse space. FLG is now widely accepted as an elementary general rule for spatial structures, and it also serves as a starting point for the measurement and simulation of spatially autocorrelated structures.

Although often deployed only implicitly in social physics (e.g., the gravity model) and in some quantitative methods (e.g., the inverse distance weighting method for spatial interpolation, regionalized variable theory for kriging), FLG is central to the core of geographic conceptions of space as well as spatial analytical techniques. With continuing progress in spatial analysis and advances in geographic information systems and geographic information science, new life will continue to breathe into FLG as we become better equipped to conduct detailed analyses of the “near” and “related.” New measures for spatial autocorrelation (e.g., local indicators of spatial autocorrelation [LISA]) have been developed to empirically test FLG in physical, socioeconomic, and cultural domains.

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