Geography Reference
In-Depth Information
Weighted factors are often used to determine suitability. The weights adjust the
factors for subjective values.
tion patterns to establish geographical relationships. Among these relation-
ships are distances of settlements to water bodies, trails and roads, and areas
with different types of agriculture. These relationships can be quantified as
measured distances and used to establish areas of potential settlements, agri-
culture, and habitation. These areas can be combined by using an overlay
operation or geostatistically analyzed to assess the combined potential that
any particular area was used by the past culture. This type of application is
helpful in planning potential archeological digs. It can be extended and
detailed in a variety of ways.
The use of geostatistics in archeological analysis such as this example
may involve a simple factor analysis of the geographical relationships. A
fac-
tor analysis
is an explanatory analysis technique that lacks an assumption that
the factors are independent. The factor analysis is therefore prone to sub-
stantial variability arising in the determination of factors and the assignment
of weights (see Figure 14.5). Why, for example, does the distance to water
bodies have a weight of 0.2 while the proximity to trails and roads only has a
weight of 0.1? The sense of these weights is not transparent, but takes into
account the specialized knowledge of the archeologist. The explanation may
help, but if the factors and weights are badly chosen, they may lead to mis-
leading results.
Types of Terrain Analysis
Another way to distinguish different types of terrain analysis is to distin-
guish between two-dimensional and three-dimensional terrain analysis.
While there is a fuzzy boundary between the two and this division means
separating the visual presentation of results from the analysis, the distinc-
tion helps one to get a basic grasp on fundamental types of terrain analysis.
Two-dimensional terrain analysis, or 2-D, usually relies on the use of ras-
ter data to analyze relationships based on location. A common 2-D raster ter-
rain analysis is visibility analysis called “viewshed analysis.” This operation
assesses the area of cells that can be seen from an origin, a raster cell, by
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