MEaSUREs InSAR-based Antarctica Flow Vectors, resampled at every 20 km. For description of velocity map in general, see the ice flow speed layer. Rignot, E., J. Mouginot, and B. Scheuchl. 2017. MEaSUREs InSAR-Based Antarctica Ice Velocity Map, Version 2. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/D7GK8F5J8M8R. Download: 12 April 2018 Original data include x and y components (VX and VY, respectively) projected to EPSG3031 at 450 m resolutions. It is resampled at 20 km intervals, and the flow direction sym_angle (degrees) is derived using sum_angle = arctan(VY/VX). The arrow length sym_length is exponentially proportional to the speed, i.e. sym_length = log_e(sqrt(VX^2 + XY^2). Other minor arrow shapes slightly depends on the speed. As a condition of using these data, the authors request that you acknowledge the authors of this data set by referencing the following peer-reviewed publication. Rignot, E., J. Mouginot, and B. Scheuchl. 2011. Ice Flow of the Antarctic Ice Sheet, Science. 333. 1427-1430. https://doi.org/10.1126/science.1208336 Mouginot, J., B. Scheuchl, and E. Rignot. 2012. Mapping of Ice Motion in Antarctica Using Synthetic-Aperture Radar Data, Remote Sensing. 4. 2753-2767. https://doi.org/10.3390/rs4092753 Editor Anne LeBrocq A.LeBrocq@exeter.ac.uk Author Rignot et al / NSIDC nsidc@nsidc.org Old Version 1 (900m, 2011): https://nsidc.org/data/NSIDC-0484/versions/1