Reconstructions of detailed geologic histories of basins have become an increasingly important part of the exploration process. However, a history that includes numerous stratigraphic horizons and several periods of orogeny and erosion usually involves handling such a great volume of data that use of a computer becomes necessary. A complete depiction of the geological history of a basin must include the geometric relationships between the various horizons (onlap, offlap, truncation, etc), the depths and thicknesses of the formations, and the effects of orogeny and erosion throughout the basin.

Most computer mapping programs generate interpolated grids that are used for drawing contour maps. These grids and maps can show configurations of horizons at various stages of basin development, and can also show pre-erosional and pre-orogenic forms. The procedures are: (1) Interpret major geologic events. (2) Capture data at each selected control point (elevations of each mappable horizon and unconformity, estimates of loss in thickness due to erosion, estimate tectonic tilts and structures). (3) Construct grids (prepare data, construct grids of present stratigraphy, construct grids of pre-erosional forms). The resultant grids are used to depict present structure, paleostructure, map isopach units, and draw stratigraphic cross sections.

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