Maps, open data and activism on the Heygate estate

Andy Allan’s excellent post on cycle campaigning reminded me to blog about some mapping help I’ve given a campaign group called the Elephant Amenity Network. One of their long-running issues has been the clearance and demolition of the unfairly maligned Heygate Estate, over 1000 council homes that should have been refurbished for council tenants instead of being knocked down for aspiring home owners to move into the area.

One of the best features of the Heygate Estate is the urban forest that has grown there in the past thirty or forty years. But the few remaining residents and local campaigners fear the “regeneration” will see many or even most of them cut down.

Through a friend who is involved with the campaign, I came along to help them map the trees that are there now. Knowing what you have seems like a good first step to saving it.

So I helped them enter the trees into OpenStreetMap using the OpenEcoMaps install of the Potlatch 2 editor, set-up a simple map that shows them as clickable objects on a map, and provided them with a spreadsheet of all the data at the end of the process.

Some other clever bods in the campaign then used a system called CAVAT (Capital Asset Value for Amenity Trees) that puts a financial value on the trees. They estimate the value to be well in excess of £7.6m! Here is the CAVAT valuation laid on top of OpenStreetMap:

I’m glad to say this has become a case study in a recent London Assembly report into the state of street trees in London, which makes recommendations about the need for open street tree data and uses this Heygate mapping to show both the demand for this data and how useful it can be.

Since mapping the trees ourselves, I’ve received a file with all the trees in Southwark from the council with permission to use and share it, which is brilliant. I did a test import in East Dulwich/Peckham Rye, but stopped short because of rendering issues. It would be great to be able to import the lot and see if citizens can keep the data more up to date than the council, or perhaps even collaborate with the council and Trees for Cities?