Wednesday, July 4, 2018

Cracking open 30+ years of Australian Landsat satellite imagery archives

Thanks to a recent technological breakthrough, the Australian public is now able to view and interact in real time with the national collection of Landsat satellite imagery. The entire 32 years of archival data - 300TB in total - can now be searched and displayed in the new innovative browser-based desktop and mobile app un|earth::. This app is accessible for free from

[Perth.Australia - Landsat 8 image: natural color RGB (bands 4-3-2) - brightness, contrast and exposure adjusted]
un|earth:: is first and foremost a demonstration of a very innovative technology but its ultimate purpose is to introduce remote sensing analysis concepts to a wide range of potential users. The app is working proof that it is viable to deliver low cost, advanced spatial analytics capability to the mass market. Hence, as of now, just about anyone will be able to benefit from the publicly available satellite imagery archives, and the privilege of utilising this national treasure will not be restricted to only a narrow group of traditional remote sensing data users.

The Australian Landsat archive is a historic record of landscape change over the last 32 years - change which was shaped by events like droughts, floods, bushfires, cyclones, land erosion but also urban expansion, land clearing, mining, crop growing, grazing and similar human activities.

The collection contains images of Australia acquired by Landsat 5, Landsat 7 and Landsat 8 satellites since 1986. There are over 3 million individual pieces of data to browse through. The archive is still growing, with imagery acquisition occurring up to six times a day over various parts of Australia every single day. Updates are released to the public on a regular basis, so the latest imagery is no more than just a few weeks old.

With pixel size of 25m, Landsat satellite imagery is ideal for local, regional and continent-scale analysis. A unique feature of the Australian collection is that the data is distributed in an "analysis ready" state - which makes it easy to compare the data through time and between various locations, but also with data from other satellites and with various resolutions. This is unlike other public Landsat data versions available directly from the USGS or through other third parties.

[Cowra.Australia - Landsat 8 image over Open Street Map: fractional cover - red: bare soil, green: photosynthetic vegetation, blue: non-photosynthetic vegetation]
The Australian Landsat archive is managed by Geoscience Australia and is accessible via the National Computational Infrastructure public website under the Creative Commons Attribution licence. Which means anyone can make a use of this data and for any purpose - whether it is public, commercial or private.

The data has been available for download for some time now but not in the synthesized format which is ready for immediate online use. A break-through innovation implemented in the un|earth:: application makes it possible to access and analyse all that historical Landsat data with just a web browser.

Experience un|earth:: first hand by visiting - more information about its current functionality in a recent media release.