Flying down the Helheim Glacier in Greenland as ATM altimetry date is shown - first with data from 1998 then data from 2013 is added
These visualizations show data from the Helheim Glacier in Greenland collected by Pre-Icebridge in 1998 and Operation Icebridge in 2013. Data from both the Airborne Topographic Mapper (ATM) and the Digital Mapping System (DMS) are included.
The first visualization shows how the scanner on the aircraft acquired the data, building up a representation of the 3d laser scanned points as we go. Once the calving front from 1998 is revealed, the 2013 data is faded in showing the differences between the years. The dots are colored initially by absolute height with reds higher and blues lower; after the 2013 data is added, the dot colors change to a localized scheme with reds higher than nearby points and blues lower than nearby points. ATM data is added at the end for some context.
The second visualization shows the DMS data with ATM data at the 2013 calving front. The DMS data is overlayed onto photogrametrically determined altitudes which don't precisely correspond to the ATM data. The heights of the ATM data are the 'true' heights.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 184.108.40.206.0