Columbia Glacier, Alaska, USA Timelapse 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 This dataset contains timelapse images taken at the Columbia Glacier in Alaska. Images were captured by several cameras placed in several locations, as denoted by camera ID (e.g. AK01, AKHS2). Images were gathered from 25 June 2004 through 14 June 2011. The timelapse images and their derivatives are organized into a set of TAR files that all follow the same structural convention: /AK01 % Camera ID /AK01_20070817 % Service Date AK01_20070512_180234.JPG % Images AK01_20070512_180709.JPG AK01_20070512_180709A.JPG AK01_20070512_180709B.JPG ... (/clock) % photos of GPS clock taken with camera (/pano) % panoramic photos from camera station (/rig) % photos of camera installation /AK02 ... /CGZM The structure within a TAR file is broken down first by camera ID, then by service date of the camera. Service dates are hardcoded into folders, as "YYYYMMDD", while image filenames carry the full capture time, as "YYYYMMDD_HHMMSS". A capital letter, starting with "A" and proceeding alphabetically, is appended to the end of the filename as needed to avoid duplicate names when multiple images were captured in the same second. In some instances, a "/clock" subdirectory (photos taken by the camera of a GPS reference clock) is included inside the Service Date subdirectory. Camera ID subfolders may also contain subdirectories "/pano" (panoramic sequences from camera station) and "/rig" (photos of camera installation). Every camera position used at the Columbia Glacier is assigned an ID (eg. "AK01", "CG04"), and significant changes in camera orientation or position are noted by a lowercase letter (eg. "AK01b", "AK01c"). "AKHXX" indicates a high speed camera; "AKSTXXA/B" denotes a stereo camera. Refer to the TimeLapse Inventory for further details about each camera and image sequence. // Data Types TimeLapse_Originals/HiRes Images exactly as they were captured by the camera, with only minor metadata changes applied. The images are first renamed according to the convention _YYYYMMDD_HHMMSS. The original capture time is printed to the caption field in the format "". All images are annotated with "Columbia Glacier", "Alaska", "USA" in the Keywords, Location, State and Country fields. In this way, the original capture time survives future changes to the clock metadata, and all files carry basic identifying information. Any color classes, tagging and star ratings applied by Shad O'Neel and Tad Pfeffer before 2010 have been preserved. TimeLapse/HiRes Complete copy of the TimeLapse_Originals/HiRes file structure, with time adjustments applied (and files renamed as needed) to synchronize all camera clocks to UTC. We highly encourage the use of these images over the originals. For sequences that lacked proper time calibration (eg. reference photos of a GPS clock), synchronization was accomplished retroactively by identifying environmental events of known time (eg. tides, sunrise and sunset, peak darkness, calving event recorded by seismometer). All "noon" images (nearest to UTC 20H) are rated 3 stars (* * *). In some sequences, if the glacier was not visible in the noon image, and a clearer view was available close in time, the noon image was rated 2 stars and the replacement 4 stars. All color ratings are for our reference only, and can be ignored by other users of the data. TimeLapse/LoRes_Tagged All timelapse images time-corrected, resized to 968x648 pixels, and timestamped with " YYYY/MM/DD HH:MM:SS". TimeLapse/LoRes_Tagged_Movies Timelapse movies of the LoRes_Tagged images encoded in MJPEG (Motion JPEG) codec at 24fps. Each movie file is derived from the images contained within the Service Date folder of the same name.