all the P.L. 94-171 products. For Boone County, this included Voting District Outline Maps, the P.L. 94-171 County Block Maps, a 1988 Dress Rehearsal TIGER/Line™ file, data listings, and a computer file providing the P.L. 94-171 population and housing data in the hierarchical format proposed for use in the 1990 census. The delivery schedule mirrored the planned delivery of P.L. 94-171 data and geographic products in the spring of 1991.
Based on the feedback from the 1988 Dress Rehearsal, the Census Bureau made several additional changes to its geographic plans for the 1990 Redistricting Data Program. First, the Census Bureau adopted the suggestion that it distinguish true VTDs from pseudo VTDs as an option for participating States. (True VTDs are those for which the boundaries shown on the Census Bureau’s maps conform exactly to the boundaries that appeared on the local source maps; all other VTDs are termed pseudo VTDs, either because the State staff modified their boundaries in some way to conform to the Census Bureau’s visible feature criteria for block boundaries or because the State staff identified default VTDs in a county for which local officials did not identify true VTDs.) Where States did not opt to provide this identification, the Census Bureau defaulted to the pseudo identification.
Second, the Census Bureau took steps to include, in its data products and the TIGER/Line™ files, latitude and longitude coordinates for a point internal to each census block (often referred to as a block centroid even though it might not be at the true center of the block). Finally, the Census Bureau attempted to implement a suggestion that would have allowed State staff to identify segments of a voting district boundary that were to remain coincident with the boundary of a legal entity if the underlying legal entity boundary was changed by a legal action, such as an annexation or detachment, and reported to the Census Bureau in the BAS. Because of technical and operational constraints, the Census Bureau was not able to automate this process, and the process of updating VTD boundaries to maintain consistency with the changing governmental unit boundaries remained a manual operation.
