Digital photogrammetric determination of alpine snowpack distribution for hydrologic modeling

TitleDigital photogrammetric determination of alpine snowpack distribution for hydrologic modeling
Publication TypeConference Proceedings
Year of Conference1994
AuthorsCline, D. W.
Conference Name62nd Annual Western Snow Conference
Series TitleProceedings of the 62nd Annual Western Snow Conference
Date PublishedApril 1994
PublisherWestern Snow Conference
Conference LocationSante Fe, New Mexico
KeywordsDEM, Digital Elevation Models, Sky Pond, Snow covered area

This paper discusses progress in the use of digital photogrammetry for producing two products: 1) orthophotos, from which maps of snow-covered area (SCA) can be produced, and 2) maps of the spatial distribution of snow depth, determined by subtracting a snow-free DEM from a snow-covered DEM. SCA is commonly used by snow hydrologists for modeling and other purposes. When aerial photography is used as a source for SCA, it is important that the photography is first ortho-rectified. In this paper, it is shown how digital photogrammetry can be used to produce orthophotos on a desktop computer, using ground control obtained from maps and a digital elevation model (DEM). The digital photogrammetric determination of snow depth has proved to be a much more difficult task, and results so far have been unsuccessful. Strict requirements for ground control accuracy appear to be the major constraint for this method. A brief overview of digital photogrammetry is provided, followed by a discussion of testing results from Sky Pond, an alpine basin in Rocky Mountain National Park, Colorado.