The Nature of Geographic Information

9. Stage Two: Regional Screening


CNSI considered additional disqualification criteria during the second, "regional" stage of the LLRW siting process. [View a table that lists all the Stage Two criteria.] Some of the Stage Two criteria had already been considered during Stage One, but were now reassessed in light of more detailed data compiled from larger-scale sources. In its interim report, CNSI had this to say about the composite disqualification map shown below:

When all the information was entered in to Stage Two database, the GIS was used to draw the maps showing the disqualified land areas. ... The map shows both additions/refinements to the Stage One disqualifying features and those additional disqualifying features examined during Stage Two. (Chem Nuclear Systems, 1993, p. 19)
Stage two composite disqualifying map of Pennsylvania, it's darker in the west side of the state
Figure 9.10.1 Composite map showing approximately 46 per cent of the state disqualified as a result of Stages One and Two of the LLRW site selection process.
Credit: Chem-Nuclear Systems, 1993

CNSI added this disclaimer:

The Stage Two Disqualifying maps found in Appendix A depict information at a scale of 1:1.5 million. At this scale, one inch on the map represents 24 miles, or one mile is represented on the map by approximately four one-hundreds of an inch. A square 500-acre area measures less than one mile on a side. Printing of such fine detail on the 11" × 17" disqualifying maps was not possible, therefore, it is possible that small areas of sufficient size for the LLRW disposal facility site may exist within regions that appear disqualified on the attached maps. [Emphasis in the original document] The detailed boundary information for these small areas is retained within the GIS even though they are not visually illustrated on the maps. (Chem Nuclear Systems, 1993, p. 20)

As I mentioned back in Chapter 2, CNSI representatives took some heat about the map scale problem in public hearings. Residents took little solace in the assertion that the data in the GIS were more truthful than the data depicted on the map.