Revealing the secrets of our environment hidden in plain sight

Tracking water surface area over time with innovative analysis and visualisation of satellite data

Camellia Williams
Vizzuality Blog

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Climate change is altering our weather patterns. There’s more flooding, more drought — and this impacts on our water supplies and agriculture. Historically it’s been difficult to monitor changes that happen on a large spatial scale and this has allowed irreversible events to occur before we knew enough to do something about it.

Today, we have unprecedented access to satellite data. This means we can monitor large spatial areas in real-time. This information is essential if we are going to tackle extreme weather patterns, increase food security and guarantee clean water for everyone; some of the key building blocks of the Sustainable Development Goals and the Paris Climate Agreement. If we’re going to make smart decisions about using our natural resources, we need better ways of accessing and interpreting data.

This is why we are proud to be working with Earth Genome, an organisation that is transforming environmental decision-making. Together we’ve built an application visualising change in surface water area to prove the value of easy access and intuitive design for environmental information.

The tool shows you what percentage of the area inside the yellow box is covered in water and let’s you see how it fluctuates from year to year

Using the tool, you can select an area of interest with a bounding box and see how water surface area fluctuates year by year between 1999 and 2012. The basemap shows the static extent of water that you would find in Google or Apple maps: these boundaries don’t move. Once you’ve drawn your bounding box, a darker blue layer appears on the map, revealing just how dynamic freshwater bodies really are.

The data is from Landsat 7 annual composite imagery, available at 30-meter resolution. The back-end built by Earth Genome spits this out through RESTful web APIs, which means anyone who wants the data can use it. Earth Genome said, “It’s insane that a web developer could easily and programmatically access Justin Bieber’s latest tweet, but could not access the extent of surface water or the intensity of deforestation with the same ease — until now.”

We built the front-end of the application, designing and building it in just two weeks using agile approaches that let the team create a high quality product in this short amount of time. We used Redux to manage the state of the application (e.g. the year being shown), meaning we could bring together and update all the components of the application more easily when you trigger a change in the visualisation (like looking at a different year). You can check out the code here.

This application is just the beginning. We’ve proved that you can have easy and intuitive access to large-scale spatial and temporal information, now it’s time to see it in action. Imagine dozens of governments working together to manage withering lakes and reservoirs. Businesses witnessing the risks of water scarcity and taking action. Or you, right now, checking out if your nearest water body contracted over the last 15 years?

Try the tool for yourself at water.earthgenome.org.

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Camellia Williams
Vizzuality Blog

Former Lead Writer at Vizzuality, for whom I wrote many of my blogs. You can now find me on LinkedIn.