Lower Rio Puerco 1970s georeferenced aerial photographs

The 1970s images were obtained as digital scans on CDs, with no metadata. Source information for the original aerial photographs is not available. Original photo scale was about 1:40,000 for the 1975 images (filenames beginning "r75")and 1:12,000 for the 1979 images (filenames beginning "rfl"). I registered and rectified these images using identifiable common points from 1996 DOQQs. See the description of positional accuracy below. Data derived from features mapped from the 1970s images were presented in: Friedman, J.M., Vincent, K.R., Griffin, E.R., Scott, M.L., Shafroth, P.B., and Auble, G.T., 2015, Processes of arroyo filling in northern New Mexico, USA, GSA Bulletin, 127(3/4), 621-640. doi: 10.1130/B31046.1