Terrain Slope

Land Usev00.10 credits/per_km2

Responsible:Niccolò Calandri

Terrain slope in degrees (0-90) computed from the USGS SRTM digital elevation model. The SRTM mission (Shuttle Radar Topography Mission) acquired near-global elevation data in February 2000 at 1 arc-second (~30m) resolution. Slope is derived using the finite difference method on the DEM grid via Google Earth Engine's ee.Terrain.slope() function.

Data Sources & References

Sources

USGS_SRTM_003

Methodology

Terrain Slope

Overview

The Terrain Slope layer computes the steepness of the ground surface in degrees (0-90) from the USGS SRTM DEM at 30m resolution.

Calculation Methodology

Load SRTM GL1 elevation (USGS/SRTMGL1_003) from GEE at 25m output resolution
Apply ee.Terrain.slope() — 3x3 finite difference kernel (Horn's method), output in degrees
Reproject to EPSG:3857 at 25m
Clip to area of interest
Quadrant split + merge for large areas

Output: degrees (0 = flat, 90 = vertical)

Data Sources

Code	Provider	Resolution	Year
`USGS/SRTMGL1_003`	NASA/USGS	30m	2000

References

Farr et al. (2007). Reviews of Geophysics, 45(2).
Horn (1981). Proceedings of the IEEE, 69(1).