Once the polygons have been created, they are attributed accordingly. This final polygon product allows for maximum flexibility for analysis and conversion in a GIS.
This is an example of one of the problems associated with combining rock formation data for a large area. Kentucky was originally field mapped over a span of 18 years. During this time, the stratigraphic nomenclature and interpretations of formations changed. The result of these changes was that different formations and members were mapped in many adjacent quadrangles. To combat this problem, before a quadrangle is digitized, a new stratigraphic interpretation, based on knowledge of the original mapping criteria and present-day interpretations, is applied, and the formations and members are grouped to provide consistency across the State. In this example, not all of the formation boundaries were digitized because of these new interpretations, so not all of the original mapped formations are present. In other cases, additional formation boundaries are mapped based on available data. All quadrangles released will have a description of the formations along with interpretations and reasons for these interpretations in the metadata.