The study details the workflow for analyzing topographic data using two primary datasets: the 250 m GMTED (Global Multi-resolution Terrain Elevation Data) and the 90 m SRTM (Shuttle Radar Topography Mission). Source layers consist of raw elevation data from these datasets, with GMTED used for its global coverage and higher resolution. Derived topographic variables—15 in total, including slope, aspect, and curvature—were calculated using a moving window analysis.
Aggregated variables were then obtained by coarsening spatial grains to 1, 5, 10, 50, and 100 km using various metrics. The SRTM data supplemented GMTED for validation and comparison. The workflow involved parallel processing and utilized open-source software tools, optimizing calculations for large raster datasets.
The study emphasizes the importance of derived topographic variables for understanding landscapes, highlighting methods for both continuous and categorical variables that represent geomorphological features. It offers insights into terrain heterogeneity and curvature, essential for ecological and geographical analyses.
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