Preliminary geologic map of the Newbury Peak 7.5' quadrangle, southern California: A digital database

The geologic map information was digitized from stable originals of the geologic maps at 1:24,000 scale. The author manuscripts (pencil on mylar) were scanned using a monochrome scanner with a resolution of 800 dots per inch. The scanned images were vectorized and transformed from scanner coordinates to projection coordinates with digital tics placed by hand at quadrangle corners. The scanned lines were edited interactively by hand using graphical user interface ALACARTE (Fitzgibbon, 1991, Fitzgibbon and Wentworth, 1991, Wentworth and Fitzgibbon, 1991). Scanning artifacts significant for display at a scale of 1:24,000 were corrected. The base map layer (nb-topo) was prepared by scanning a scale-stable composite negative of the Newbury Park 7.5 minute topographic map (1967 edition). The negative was scanned using a monochrome scanner with a resolution of 400 dots per inch. The raster scan was converted to a GRID in ARC/INFO. The GRID was then vectorized and reprojected into State Plane Projection using the four corner tics as reference points. The arcs in the base layer have not been attributed.