Tag Archives: Trees

London’s natural geography

I’ve been playing around with open data from OpenStreetMap and Natural England to make a pretty map of “green and blue infrastructure” in London. Here’s the result:

You can download a PDF version suitable for printing here: natural_london.

I’m pretty happy with the result, my first real attempt to produce something useful with QGIS. The data I used was:

There’s no reason the Natural England data couldn’t be manually added to OpenStreetMap, giving us a complete dataset of natural features. I just chose to get on and do it this way rather than wait, or try to add all the data across areas of the city I don’t know well and am not going to visit any time soon. I also didn’t really need to use the Ordnance Survey data for boundaries, but it’s slightly more accurate and complete than OpenStreetMap data.

The map is probably missing lots of smaller patches of green space, including grass verges, green roofs and biodiverse brownfield sites. The biggest omission is the humble private garden. They cover 24% of London’s land!

But the map at least shows the more obvious, visible, public green spaces, and is a nice example of what a geek with no GIS training (but years of playing with OpenStreetMap) can do with free software and free data these days.

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Mapping for pedestrians

One of the odd things about contributing to OpenStreetMap is that you have no idea who is using the maps and the data. You spend hours, weeks, months, years even building up a wonderfully comprehensive database of geographic features in the area, all because it’s fun, because you believe in the project’s ideals or you need the data for your own project. But does anyone else use it? It would be depressing if the answer was “no”.

So I get cheered every time I see documents like this:

That’s an excerpt from a presentation by Southwark Living Streets. They took the Mayor of London’s transport advisor around Elephant & Castle to show how unfriendly and dangerous the area is for pedestrians, and illustrated the whole thing with OpenStreetMap. The chap who made this loves OSM, he told me he realised how useful it could be when he noticed we had put in all the footpaths through estates, making OSM the only map that reflects the reality for pedestrians in the area.

It was our coverage of footpaths that led to OpenStreetMap being used by parents challenging a school’s decision that they were outside the catchment area.

I also regularly see OSM used by cycling campaigners, for example this presentation on a cycling campaign that’s also about the Elephant & Castle area.

Then there was my collaboration with residents local to the Heygate Estate who wanted to map the trees that under threat from the redevelopment of the estate. That, I’m happy to say, has resulted in many of the mature trees being protected in the new plans.

So we have useful maps, and powerful tools for community campaigns if there’s an OSM expert about to help out.

But as I wrote last year, there’s a whole other world of data we could be adding, especially for groups concerned with streets that are designed for pedestrians and cyclists.

ITO have been beavering away on lots of amazing maps that show off this kind of data. These are two maps showing the “walkable city” on the left (the blue lines show footpaths and pavements broken up by black roads) and speed limits on the right (green is for 20 mph, orange for 30 mph).

Here are a few in an area I’ve done some work on, just to show what’s possible:

With a few tweaks to the Potlatch 2 editor on the OpenStreetMap homepage, anyone could easily add all this metadata to streets. There are presets for speed limits and surfaces, but not – yet – for sidewalks. If we could get them in – here’s the enhancement request – I think all those community campaigners already using screenshots of OpenStreetMap might just get interested in contributing data.

How great would it be if Southwark Living Streets could print out a special “walkable city” map of Elephant & Castle for their next presentation to the Mayor of London’s transport advisor?

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Open scrutiny in the age of open data

This is the first of perhaps two or three short essays inspired by Emer Coleman‘s masters dissertation on open data, written in a personal capacity and not as part of my job. In this post I want to look at what her proposed model of “iterative and adaptive open government” would mean for scrutiny of the Mayor of London. Her dissertation considers the difference between the New Public Management approach, characterised by public managers setting the goals and other public managers auditing their performance, and an emerging “Open Governance” approach using open data.

Continue reading

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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.

A photo of the Heygate Estate in Elephant & Castle, London

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?

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