By Amy Palmer-Newton, GiGL Database Officer

Since the start of 2021, the GiGL team have been hard at work updating and improving our Areas of Deficiency (AoD) models. We’re excited to announce that these are nearly ready for launch, and we can’t wait to share the new features we can offer to our partners and clients.

Although the concepts behind AoD are quite simple, the modelling itself is anything but. This article will explain what AoD is, the changes we’ve made and what this means for our services going forward.

What are AoD?

Areas of Deficiency are a meaningful measure of access to open space and nature in London. They are defined as areas outside of a specific walking distance from sites that meet particular criteria. GiGL have developed two AoD datasets:

1) AoD in Access to Nature

Also known as SINC AoD, these are areas over 1km walking distances from accessible Sites of Importance for Nature Conservation (SINCs) of borough-grade or above. SINCs are London’s Local Wildlife Sites, recognised for the important habitats they support. They are designated by Local Authorities in their non-statutory planning policies, and are selected with assistance from local ecological professionals. You can read more about SINCs on our website.

2) AoD to Public Open Space

Also known as POS AoD, these are similar to SINC AoD but based on different walking distances for different categories of Public Open Space (POS).

Public Open Spaces are sites which meet the criteria given in Policy G4 Open Space of the London Plan. There are seven different categories, based on the size of the sites and the facilities they offer. You can find out more about POS sites on our website.

Why are AoD important, and what are they used for?

AoD give an indication of whether people living and working in a given area can easily visit Public Open Spaces or wildlife sites. This takes into account the distribution of sites within an area of interest and the effect of sites in neighbouring areas too.

AoD mapping is used by Local Councils to assess open space provision in their boroughs. The London Plan states that Local Councils should reduce deficiency in access to open space and to nature. To achieve this, they need to know where the deficient areas are and understand their causes.

Students and researchers also use our AoD mapping in their projects: analysing it against other datasets to find out whether living in AoD correlates with factors such as health, crime rates or house prices. With access to census data, AoD maps can be used to calculate statistics on the numbers of people living in AoD, which can provide further detail for policy making or research.

There are numerous ways that AoD can be utilised by our diverse assortment of partners and clients including in campaigning, education, journalism, historical studies and artwork. Our new AoD model will help expand and diversify these end uses even more.

Measuring AoD

The way we measure AoD hasn’t changed. We still use software that calculates the actual walking distances from site access points along walkable roads and paths, and adjust the buffers accordingly using a clever piece of network analysis. To do this we use our dataset of site access points (some from site surveys and some inferred from other data) and a digital map of the roads and paths network in London maintained by Ordnance Survey.

The areas that are outside of these walking distance zones (known as isotimes) are the AoD, as they as too far from a suitable site.

A more in-depth look at the methodology is outline in a previous GiGL newsletter article.

So what’s changed, and why?

Although the core methodology hasn’t changed, there has been a big update in how we run our calculations and we have greatly expanded what the model can do. A more streamlined method using up-to-date tools and road network data has been developed, building on the reliable model previously used. We have also moved software to enable faster and more efficient processing. And we’ve added easy to use customisable features to allow the model to be tailored for a wide variety of uses.

The result provides even more scope for predictive and custom modelling. For example, we can now model AoD to show how changes to site boundaries or their access will impact AoD. We can also model AoD for specific sites and distances, such as how many people live within 1 km of an accessible play area. If we have the sites, access points and distance parameters, we can do this anywhere within Greater London.

This flexibility gives us greater scope to help planners explore the different options for reducing AoD. This can be done by creating more sites or expanding their area; by improving the quality of open spaces so that they become suitable Public Open Space or SINCs; or by improving access to existing sites by adding entrance points, removing access restrictions or improving local walking routes.

This updated model may lead to a number of changes in GiGL’s AoD map when compared to the old map. Some changes may be as a result of using an updated road and path network, which will influence how people reach the site boundaries. Other small changes may arise from how access points are determined. We will be in contact with our SLA borough partners in the coming months to help explore and explain any changes caused by the new model and updated network for both SINC and POS AoD.

Timeline

The new London-wide SINC AoD is set to launch in July 2021, when it will be sent out to our SLA partners in our quarterly data exchange and become available to students and researchers. The London-wide POS AoD is set to follow after in March 2022.

Our partners can expect SLA Spotlight articles on specific SINC AoD updates in July and POS updates in October.
We can already offer our unique custom and predictive modelling for SINC AoD, and modelling POS AoD will be available shortly.

The new London-wide SINC AoD model

And now for a quick sneak peak of the London-wide AoD model, shown below. This is a culmination of lots of hard work from the GiGL team, and will really elevate our ability to assist partners and clients to improve access to open space and nature within our city.

Please contact Amy for any SINC AoD specific questions and contact Tanvi for POS AoD. We’d love to hear your thoughts on our AoD modelling going forward.