SRTM (Shuttle Radar Topography Mission) is over two decades old and still the most downloaded and widely cited elevation dataset in the world. Collected during an 11-day Space Shuttle mission in February 2000, it mapped roughly 80% of Earth's land surface in a single consistent pass — and that consistency is why it persists as the default DEM despite newer alternatives existing.
Copernicus DEM offers more recent data and polar coverage; ALOS World 3D provides comparable resolution with broader latitude range. But SRTM has the deepest ecosystem of derived products, the most published validation research, and the longest track record in operational use. It's the elevation data that HydroSHEDS is built on, that MERIT DEM corrects for vegetation bias, and that countless slope, watershed, viewshed, and flood models have been calibrated against.
The important caveat is that SRTM is a Digital Surface Model, not a bare-earth DEM — it captures the top of canopy, buildings, and structures, which means it overestimates ground elevation in forested and urban areas. For applications where this matters (precise hydrological modeling, infrastructure engineering), MERIT DEM provides a corrected version with vegetation bias removed, and LiDAR-based DEMs offer true bare-earth measurements where available.
For the broad majority of regional terrain analysis — slope calculations, watershed delineation, viewshed mapping, road corridor planning — SRTM's combination of resolution, coverage, and zero-cost accessibility makes it the practical starting point. Use it as the global baseline and upgrade to more specialized elevation data where your application demands it.
