Retrieve SRTM tiles | Last update: Oct. 2016 |
This service provides a TIFF image with values from the SRTM (Shuttle Radar Topography Mission) Digital Elevation Model.
Available worldwide and for free. WGS 84 projection (=constant step in latitudes and longitudes).
Command:
http://www.webservice-energy.org/mapserv/srtm?SERVICE=WMS&
VERSION=1.3.0&REQUEST=GetMap&
BBOX=min_lat,min_lon,max_lat,max_lon&CRS=EPSG:4326&WIDTH=nb_pix&HEIGHT=nb_pix&
LAYERS=srtm_version&FORMAT=image/tiff
with:
- min_lon: west bound of your bbox
- max_lon: east bound of your bbox
- min_lat: south bound of your bbox
- max_lat: north bound of your bbox
- nb_pix: size of the image in pixels
- srtm_version: srtm_s0 (full resolution, 16 bits), srtm_s2 (½ resolution srtm_s0), srtm_s4 (½ resolution srtm_s2), or srmt_s8 (8 bits, ½ res. srtm_s4)
Characteristics:
The webservice supplies a map of max 2048 by 2048 pixels. Where SRTM is not defined, i.e. in the water areas, value is -32768 or -2ˆ15. The highest spatial resolution is 5°/6000 pixels, which means that 1 pixel corresponds to 0.000833° (= 3" = 3*1/3600). If you request a pixel size higher than the spatial resolution, an undersampling operator is applied to create a coarser image. Whereas, if the requested pixel size is smaller than the spatial resolution, a bilinear oversampling is applied on the image.
Don't hesitate to explore the webservice-energy.org catalog.
Example
Retrieve the SRTM tile over Corsica (right illustration =>) | |
Over the reunion Island - 1 km spatial resolution: http://www.webservice-energy.org/mapserv/srtm?SERVICE=WMS&VERSION=1.3.0&REQUEST=GetMap&BBOX=-22,55,-20,56&CRS=EPSG:4326&WIDTH=120&HEIGHT=240&LAYERS=srtm_s0&FORMAT=image/tiff NB: the location of the centers and corners of the MSG pixels are overlayed on the DEM. | ![]() |