Digital Geography

7. October 2015

Short Announcement: SRTM 1 Data Worldwide

The digital elevation dataset resulting from the SRT Mission in the year 2000 is probably the most widely used digital elevation dataset in the world. It was first released with a 90 at ground resolution in a more or less global level (56° S to 60° N). In 2014 the White House announced the release of the 30 m original solution dataset. So they released parts of the dataset one-by-one. Our author Christoph just mentioned an update via Twitter.

SRTM 1

The schedule was like this:
  • November 2014: Mexico, South America
  • January 2015: Australia, Southeast Asia
  • April 2015: North America, Europe
  • July 2015: China, Japan
  • September 2015: Northeast Africa
And by looking on the calendar we checked back again: The gaps of the dataset are now filled and you can download this great resource for free:

global coverage of the SRTM 1 dataset

To work with data you only need an account at the GLCF website. As an alternative I would like to point to another resource for elevation data. The website www.opentopography.org provides access to the SRTM 1 dataset via an Rest API. The only thing needed?
demtype The SRTM dataset – Global 90m is ‘SRTMGL3’ and Global 30m is ‘SRTMGL1’
west, south, east, north WGS 84 bounding box coordinates
outputFormat Output Format (optional) – GTiff for GeoTiff, AAIGrid for Arc ASCII Grid, HFA for Erdas Imagine (.IMG). Defaults to GTiff if parameter is not provided
So by calling a URL like
http://ot-data1.sdsc.edu:9090/otr/getdem?demtype=SRTMGL1&west=100&south=48&east=101&north=49&outputFormat=GTiff
You might get a nice DEM for the desired area as download and to use in your favourite GIS:

SRTM 1 extract in QGIS

At the moment I would prefer to work with this SRTM 1 dataset as it is shipped by a manifold of services, reliable, more or less a current DEM. Compared to ASTER (artefacts as fuck!) and ALOS 30m (will be available worldwide someday) I would grab the NASA data without the blink of an eye. But hey, it depends on your research question or the requirements of your project whether this dataset will please you…

When it comes to height data: what do you prefer and in which project did you used it?