methods of analysis of Las Marias study area:

1. scan and import black and white panchromatic aerial photographs into the image processing package ERDAS Imagine
2. register the 1982 photograph to a 1994 Landsat image with a series of several ground control points
3. register the 1946 photograph to the registered 1982 photograph with a series of ground control points
4. define the projections of the registered photographs
5. overlay the photographs to compare river location across the two time periods
6. compare river position between 1946 and 1982
6. digitize the area of overlapping coverage from the 1946 and 1982 photographs
7. digitize forest areas in two photographs
8. compare change in river surface area and surrounding forest area between 1946 and 1982