Scale

The issue of scale is not new, nor is it a concern restricted to geographic information scientists. Scale variations have long been known to constrain the detail with which information can be observed, represented, analyzed, and communicated. Changing the scale of data without first understanding the effects of such action can result in the representation of processes or patterns that are different from those intended. For example, research has shown that reducing the resolution of a raster land cover map (going to larger cells) can increase the dominance of the contiguous classes, but decrease the amount of small and scattered classes (like wetlands in some locations) in the representation (Turner et al., 1989). The spatial scaling problem presents one of the major impediments, both conceptually and methodologically, to advancing all sciences that use geographic information. Likewise, temporal scaling, a separate but related issue, is not well understood and thus difficult to formalize. In an information era, massive amount of geographic data are collected from various sources, often at different scales. Before these data can be integrated for problem solving, fundamental issues must be addressed.