Current Trends in Geomathematics pp 9-18 | Cite as

# Methods of Thematic Map Comparison

## Abstract

Geologists are interested in comparing maps in order to (1) determine their predictive value, (2) evaluate their similarity and classify them, and (3) use the information for geological interpretation. The comparisons are made by constructing a difference map (isopachous maps) or on a point-by-point basis (computing an overall correlation coefficient for the fit).

Alternatively, surfaces may be represented by numerical descriptors which can be used as the basis for comparison. The original data points need not be at the same location so that different geographic areas can be compared. However, a uniquely defined spatial grid mesh must be overlain on each data set for the purpose of interpolating grid values which may be compared quantitatively. The interpolated grid values then are compared to determine “reliability indices” at individual grid node locations. This newly generated grid matrix is contoured and shows in two dimensions which areas are most alike and which ones are most dissimilar.

## Keywords

Reliability Index Geological Interpretation Trend Surface Original Data pOints Prospective Petroleum## Preview

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