Repeat photography is a technique in which a historical photograph and a modern photograph, both having the same field of view, are compared and contrasted to quantitatively and qualitatively determine their similarities and differences. The following sections depict how this technique was used at a number of locations in Alaska, including Glacier Bay National Park and Preserve, Kenai Fjords National Park, and the northwestern Prince William Sound area of the Chugach National Forest, to document and understand changes to glaciers and landscapes as a result of changing climate. Through analysis and interpretation of these photographic pairs, information is extracted to document Alaskan landscape evolution and glacier dynamics for the last century-and-a-quarter on local and regional scales and the response of the Alaskan landscape to retreating glacier ice.
