Good evening everyone!!
TL;DR: Great news, free ~5 m satellite imagery for the tropics. Comes analysis-ready in RGB, download coming mid-October via Planet Explorer. There are also other free options if you need more from your satellite imagery.
A number of people have been sharing the very exciting announcement that, thanks to a collaboration between NICFI, Planet, Airbus, and Kongsberg Satellite Service, high resolution imagery is going to be made available for free! There are some press releases attached in a few different languages for more info. This is amazing news – we can’t wait to use it – but we thought it would be worth noting a few things that are often missed from the headlines.
Here’s a breakdown of the essentials:
- The mosaicked imagery is 4.7 m resolution and only covers tropical landmasses that sit between 30 degrees North and 30 degrees South.
- They will be released monthly, completely free of charge, and free for use and distribution.
- Historical mosaics are also available: 6 month intervals since December 2015.
- To access these mosaics, you can view them now via Global Forest Watch, or come mid-October, you can download them via Planet’s Explorer tool.
There are some other aspects we thought to note, too:
- As mentioned above, currently the service is view only via the GFW website; anyone is free to view the mosaics and take screenshots without registration.
- The data will be ‘analysis-ready’. What this essentially means is that you won’t have to do any pre-processing on the satellite imagery. When you download the data, it will arrive in a full colour RGB image file that can be opened easily in any GIS software. More info, if you’re interested, on Planet’s Analysis Ready Data (ARD) can be found here.
- The data is set to be made available until December 2021 with the (likely?) option for extension to December 2023.
There are also some other satellite imagery options available to you other than this:
- SPOT archive data has been available for free for years thanks to the French government (archive data > 5 years old), but this has a resolution of 10 m. This is likely expected to become more streamlined with this new data due to Airbus’ involvement.
- Sentinel-2 (10 m resolution) is a freely available satellite image resource that dates back to 2016. You also get a greater number of image bands with this download (but it is not analysis ready) so this is great for a more customisable option.
- Landsat 8 and previous (30 m resolution) is another great option with a fantastic archive that dates back about 40 years.
- These may be better options; spectral resolution for example can make these data sources more suitable options for certain types of detection/mapping than higher (spatial) resolution imagery.
- To download these you can visit USGS EarthExplorer.
Happy mapping :)