Columbia Glacier, Alaska, USA Aerial Photography Collection version: 2011-10-14 // Primary Contacts Ethan Welty Institute of Arctic and Alpine Research 1560 30th Street Campus Box 450 Boulder, CO 80309 (206) 853-3712 ethan.welty@colorado.edu Shad O'Neel USGS Alaska Center 4210 University Dr. Anchorage, AK 99508 (907) 786-7088 shad.oneel@gmail.com Tad Pfeffer Institute of Arctic and Alpine Research 1560 30th Street Campus Box 450 Boulder, CO 80309 (303) 492-3480 wtpfeffer@gmail.com // Data Summary Aerial stereophotography missions were flown at least once every year over the Columbia Glacier in 1976-2010, and documented further in the Aerial Inventory. All existing scans of the large format diapositives have been included here. However, only derived data products from 2002-2010 are included, as DEMs generated from earlier flights are unreliable due to problems with ground control, and currently unfit for mass consumption. // Aerial Photographs All scanned aerial diapositives are named following the convention: __.TIF, where is the date of the flight in YYYYMMDD format, is the number of the image strip (multiple may be flown on a given date) in 01-99 format, and is the number of the image in 01-99 format. SCANS hires: Original, full resolution scans done on a photogrammetric scanner. lores: Low resolution JPG previews (incomplete). // Data Products All raster data are in GeoTiff format (*.tif) projected to WGS84 UTM Zone 6N. Elevations in the DEMs are given as height above the WGS84 ellipsoid. All files, with the exception of the velocity fields (VEL), follow the same naming convention: _m.tif, is the date of the flight in YYYYMMDD format, and is the cellsize of the raster in meters. DEM Digital Elevation Models for aerial stereographic flights 2002-2010. ORTHO Orthorectified mosaics for aerial stereographic flights 2002-2009. ORTHO_hires Orthorectified tiles processed at full resolution (0.25m) for flight 20090827. A spatial index (polygon shapefile) is included. SHADE Hillshade rasters for all DEMs 2002-2010. VEL airborne: Glacier surface velocity fields derived from ORTHOs for flight pairs in years 2004-2006 and 2009-2010. landsat: Glacier surface velocity fields derived from repeat LANDSAT imagery for years in 1989-2009. Additional documentation is provided by Yushin Ahn.