1930 Photo Mosaic - Pool 21

The U.S. Geological Survey's Upper Midwest Environmental Sciences Center (UMESC) has obtained historical photography of the Upper Mississippi River, collected by the Corps of Engineers in the 1930s. The Center uses these photos in their training program for GIS interns, to provide them with experience in georeferencing photos. Whenever enough photos are georeferenced that a mosaic can be created, the data are made available through the center's Internet site. The 1930 photo mosaic for Mississippi River Navigation Pool 21 was created using 1:12,000-scale black-and-white photos collected during 1929-1930 probably late summer). The photography was originally collected for the Brown Survey. Individual prints were trimmed by hand to make photo mosaics and these hand-cut mosaics were scanned and referenced using digital ortho quarter-quads with image source dates from the early spring in the 1990's.