Digital Data for Construction Material Sources Reported by the Arizona Department of Transportation in 1977 for Maricopa County, Arizona, USGS OFR 01-122

In the Source introduction it states: "The pit location maps show the location of all pits bearing Materials Services serial numbers. Other sources are not shown. The plotted locations are as close as possible to the true location as the scale of the map will allow." The point attribute data, captured from the Source pit data sheets are "designed to show test results (sieve analysis, plasticity index, and abrasion) for the usable material within each ADOT pit." The digital editor and digital compilers of the GIS data set made certain adjustments to the data to make them complete and usable in a GIS.

These adjustments include adding points locations for records in the accompanying Source pit data sheets where no point representation existed on the Source map sheets, adding attribution data to the furthest extent possible for points on the Source map sheets without entries in the accompanying Source pit data sheets, appending a letter to the pit number of repeated (duplicate) pit numbers to make them unique and correspond one-to-one with a record in the Source pit data sheets, and adding a '-999' to represent 'No data' or 'No observation' for blank entries in the pit data sheets.

Table 3 in the Open-File Report text describes the actions taken to insure data consistency and uniqueness of the individual points. An accompanying ArcInfo arc coverage called marbase of the generalized Maricopa County boundary, and generalized major roadways and generalized major hydrography of Maricopa County has been included to give a general reference of pit location in proximity to natural and man-made features.