Monitoring cultural heritage by comparing DEMs derived from historical aerial photographs and airborne laser scanning

Abstract

This paper presents results from a study where identification and documentation of landscape changes using a combination of historical aerial photographs and newer airborne laser scanning (ALS) data were examined. The study was based on remotely sensed data covering a Norwegian protected cultural environment consisting of several pebble-stone built grave cairns. Georeferenced digital elevation models (DEMs) were generated using historical air photographs from the years 1968, 1979 and 1999. In addition ALS datasets from 2008 and 2010 were used in the study. Altogether seven difference models were generated as a result of conducting automated change detections between the different epochs. In this way detailed information about changes that occurred in the landscape and to individual monuments for almost the last 50 years was obtained. Further, the incidents that caused the identified changes were interpreted based on documents from archives. Using this approach the dynamic character of the studied protected site was proven. The study demonstrates the importance of historical aerial photographs as a valuable source that makes possible retrospective monitoring of past landscape changes on a detailed scale.