Often visiting researchers in the park will donate photos and data if they believe it will help Denali National Park & Preserve staff manage resources. It was in this way that the park received a gift of more than one thousand 35 mm slides taken by Dr. Fred Dean, Emeritus Professor of Wildlife Biology at the University of Alaska and longtime Denali researcher.
The slides were of aerial photos taken in 1975 and 1976 from the back of a Piper Supercub airplane, as part of a project that ultimately produced the first large-scale land cover map of Denali. Dr. Dean and his graduate student, Debbie Heebner, used the photos along with a large volume of field data to ground truth proposed vegetation types shown on LANDSAT satellite imagery.
Fortunately, Dr. Dean had maintained immaculate field notes describing each slide and a set of detailed maps recording the location and direction of view for all of the photographs. Upon receiving the photos, we scanned them at high resolution, and captured all of the information on Dr. Dean’s maps and notes. During this process, we identified those photos that contained enough landmarks for relocation. In the summer of 2005 we took to the air to repeat as many of Dr. Dean’s aerial photographs as possible.
In addition to this effort, we have also assembled repeated pairs of technical aerial photos. Technical aerial photos are those taken from airplanes with equipment that captures an image’s exact location over the surface of the earth, so that it can later be rectified with a location on a map. Technical aerial photos were taken to document reclamation efforts showing the recovery of mined streams before and after reclamation work, or to otherwise get a detailed, geographically rectified look at a particular area. In some cases, quantitative change can be measured from these photo pairs because they align so well; however, since they are taken from a high elevation, detail is sometimes lost.
Return to Repeat Photography in Denali…