Florinsky, I.V., 2007. Small scale morphometric maps of the Northern Eurasia. Geodezia i Cartografia, No. 2: 15–21 (in Russian).
The study was based on a 10 arc-minutes gridded DEM of the Northern Eurasia assembled using several sources. Elevations of the land topography were derived from GLOBE. Most of the seafloor topography was taken from ETOPO2. Bathymetry of Caspian Sea and large lakes was digitised using topographic maps. To reduce noise, up to 12 iterations of smoothing were applied to the DEM using 3 x 3 kernel with linear inverse distance weights. DTMs of the following topographic variables were derived from the smoothed DEMs: twelve curvatures (horizontal, vertical, accumulation, difference, ring, minimal, maximal, mean, Gaussian, unsphericity, horizontal excess, and vertical excess curvatures), slope gradient, slope aspect, rotor, catchment area, dispersive area, and accumulation zones. Local variables were calculated by the author’s method. Regional variables were calculated by a single flow direction algorithm with removing ‘pits’ adapted to spheroidal trapezoidal grids. All DTMs produced had a resolution of 10 arc-minutes.