Visualization of VER on March 5th, 2008, at 18:41:30 UT for the 1NG line at 427.8 nm. (a) 2D projection at 100 km altitude centred on Skibotn corresponding to X = 0 km and Y = 0 km location (see the red point), (b) 3D mapping from 100 km to 240 km altitude, (c) VER field-aligned profile at different altitudes for a given location in the map (here X = −24.1 km and Y = 6.6 km at 100 km altitude).