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Full catalog/SRTMGL3S
SRTMGL3S·v003·dataset

Elevation map of Earth's land, coarser (SRTM radar, 90 m)

NASA Shuttle Radar Topography Mission Global 3 arc second sub-sampled V003
land NASA LPCLOUD Level 3 HGT
In plain English

What it measures. Ground elevation across nearly all of Earth's land, telling you how high each spot sits above sea level, at roughly 90-meter spacing.

How it's made. Created by radar flown on the Space Shuttle Endeavour during the year-2000 SRTM mission, then thinned down from the finer 30-meter version and gap-filled to remove holes.

How & where you'd use it. A widely used foundation for mapping, flood and terrain studies, and any work that needs a global picture of the lay of the land.

What's measured

SPECTRAL/ENGINEERING › RADAR › RADAR IMAGERYLAND SURFACE › TOPOGRAPHY › TERRAIN ELEVATIONLAND SURFACE › TOPOGRAPHY › TERRAIN ELEVATION › DIGITAL ELEVATION/TERRAIN MODEL (DEM)

Coverage & cadence

  • Time span2000-02-11 → 2000-02-21
  • Measured bySTS-99 (SRTM)
  • Processing levelLevel 3
  • Spatial extent-180, -56, 180, 60
  • FormatsHGT
  • StatusCOMPLETE

What you can do with it

  • Track deforestation, fire scars and land-cover change
  • Monitor crop and vegetation health (NDVI/EVI)
  • Map how built-up vs. green an area is over time
Official description

The Land Processes Distributed Active Archive Center (LP DAAC) is responsible for the archive and distribution of NASA Making Earth System Data Records for Use in Research Environments ([MEaSUREs](https://earthdata.nasa.gov/about/competitive-programs/measures )) SRTM, which includes the global 3 arc second (~90 meter) sub-sampled product. The 3 arc second data was derived from the 1 arc second using sampling methods. (See Figure 3 in the User Guide) The NASA SRTM data sets result from a collaborative effort by the National Aeronautics and Space Administration (NASA) and the National Geospatial-Intelligence Agency (NGA - previously known as the National Imagery and Mapping Agency, or NIMA), as well as the participation of the German and Italian space agencies. This collaboration aims to generate a near-global digital elevation model (DEM) of Earth using radar interferometry. SRTM was the primary (and virtually only) payload on the STS-99 mission of the Space Shuttle Endeavour, which launched February 11, 2000 and flew for 11 days. The SRTMGL3 data were sub-sampled from [SRTM1GL](https://doi.org/10.5067/MEaSUREs/SRTM/SRTMGL1.003) data that fall within that tile. These elevation files use the extension ".HGT", meaning height (such as N37W105.SRTMGL3S.HGT). The primary goal of creating the Version 3 data was to eliminate gaps, or voids, that were present in earlier versions of SRTM data. In areas with limited data, existing topographical data were used to supplement the SRTM data to fill the voids. The source of each elevation pixel is identified in the corresponding [SRTMGL3N](https://doi.org/10.5067/MEaSUREs/SRTM/SRTMGL3N.003) product (such as N37W105.SRTMGL3N.NUM). The SRTM swaths extended from ~30 degrees off-nadir to ~58 degrees off-nadir from an altitude of 233 kilometers (km), creating swaths ~225 km wide, and consisted of all land between 60° N and 56° S latitude to account for 80% of Earth's total landmass. Known Issues * Known issues in the NASA SRTM are described in the following publication: * Rodriguez, E., C. S. Morris, and J. E. Belz (2006), A global assessment of the SRTM performance, Photogramm. Eng. Remote Sens., 72, 249–260. https://doi.org/10.14358/PERS.72.3.249

Get the data

srtmgl3s_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="SRTMGL3S",
    version="003",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from LPCLOUD
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.