Mapping lies behind a lot of new digital technologies — location data powers apps which can now tell us the fastest way to get across town or where the nearest cafe is, and give you real-time spoken instructions on how to get there.

Now it’s entered the world of farming. With the crop map of England (CROME), the UK’s Rural Payments Agency (RPA) has built an interactive map to show what types of crop are grown on English farms. Based on radar satellite data from the European Space Agency (ESA), the map has allowed the RPA to make big savings and, by opening it to the public, help others safeguard England's wildlife and the natural environment.

Every cloud...

The RPA is the body which distributes EU subsidies — due under Europe’s Common Agricultural Policy — to farms in England. To receive payments, farmers submit claims every year declaring what they are growing. The RPA validates these, using a combination of inspectors, airborne surveillance and satellites.

But in 2015 part of the system to check jobs failed. “What happened is that half the control areas we wanted to check had cloud cover for the entire crop season,” said Sanjay Rana, senior GIS analyst at the RPA. “For all the satellite data we had, we could not map the crops.”

Rana’s solution was to create a new kind of map with radar images. Using data harvested by the European Space Agency’s Sentinel 1 satellite, he was able to access images unaffected by weather conditions. Rana then used a machine learning algorithm to automatically identify the crop type from the radar image — accurate in around 85% of cases — before building a map as a visual representation.

Positive side effects

Rana and his team were committed to making the map available to the public from the beginning. But their “parcels” — the regularly shaped polygon chunks of different crop types into which the RPA divides up all English farmland — were derived from a master map produced by the British mapping agency, Ordnance Survey. These are a commercial asset, so it wasn’t possible to use them on a tool available to the public.

Instead, Rana developed his own hexagonal parcels. Initially devised as a “compromise”, he said, they ended up bringing their own benefits. For example, they’re more effective than rectangles at demarcating crop types within fields, allowing for a more detailed map. “It's able to capture the arbitrary layout of the crops on the ground,” said Rana.

As such the RPA has been able to roll back the number of inspections it makes to verify claims. “In the past if we couldn't verify the crop type we had to send an inspector out,” said Rana. The RPA now does that far less, "as we're able to double check that information in the crop map". According to Rana, this has helped the RPA to save thousands of pounds a year.

Elsewhere, the UK’s environmental bodies are using the map to improve their work. Natural England, the government’s environmental advisor, uses the map data to help place protected feeding areas for water birds threatened by environmental change — bird populations can be located and protected if you know where the crops they eat are positioned.

And the British Environment Agency uses the map to select sites to monitor water quality. When land is kept bare for long periods of time, pollutants are more likely to run into water-ways. Access to CROME helps them to monitor crop levels, and more accurately work out which sites they should inspect.

Further afield

After the UK leaves the EU, the CAP will cease to apply in the UK. But the map is still useful: crops are a commodity, and the basis of financial investments. Meanwhile, Scotland’s government is interested in making its own version of the map — it can help to assess crops on remote land which inspectors find difficult to access.

The project saw the RPA shortlisted for a civil service award for innovation in 2016.

Rana stressed the importance of research work sponsored by the Defra Earth Observation Centre of Excellence, which led to the research project that influenced the map. “With the CROME product I was able to operationalise all that research knowledge,” He said. — Anoush Darabi

This piece has been amended to clarify some aspects of the RPA's organisational processes, and to reflect the role of the Defra Earth Observation Centre of Excellence.

(Picture credit: Flickr/Dave_S.)

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