Vol. 5, No. 1, 42-50, 2006

Abstract
Contrary to the standard aerial survey methods, oblique aerial photography from relatively low altitudes can often be accomplished when weather conditions preclude traditional vertical aerial stereo-photography. Therefore, a close range digital multiple-image-photogrammetry (convergent or multi-image-photogrammetry with 100% image overlap) method can be used for aerial surveys even when weather would prevent standard survey flights. The combination of a Rollei6008metric survey camera and the Polarphox photogrammetric software facilitates the measurement of changes in the ice volume of glacier ablation zones and other geomorphic features of mountain areas. A small single engine airplane with far less operational costs than the normal aerial survey airplane is ideally suited for this. A current project of the University of Göttingen will analyse ice volume changes on several glaciers in south-central Alaska. Recently, most glaciers of the region showed a significant retreat and loss of substance, which is being documented in this project. A modern digital multiple-image-photogrammetry system is used to process the imagery. Similar to stereo-vertical imagery, automated surface measurements are possible. However, photogrammetric analysis of a surface is limited in the same way traditional stereo-photo analysis is limited by a lack of identifiable features on the target. Naturally, fresh unbroken snow surfaces in the accumulation areas of glaciers cannot be measured. This paper tries to point out the advantages and limitations to this new method.

ISSN 1729-3782