This data set was produced by Spencer B. Gross Photogrammetric Engineering in Portland, Oregon for the Army Corps of Engineers and several other public agencies. The orthophotos cover the Willamette River and its main tributaries, as well as some Oregon coastal rivers and Sandy River. The source CD-ROMs held Tiff files with world files and were in the Oregon North Stateplan projection with 2 foot pixel size. We resampled them to UTM Zone 10, Clarke 1866, NAD27, 1 meter pixel size. The photos for this data set were acquired in 1994 and 1995. We used them primarily for ground checking of troublesome land cover types, but never for training or testing polygons.