This is a prototype.

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  3. Brownfield sites

Brownfield sites

Brownfield sites are plots of land that have previously been developed but are not currently in use. Recent analysis suggests more than 1 million houses could be built on brownfield sites across England.

We’re working with local planning authorities to improve the quality and availability of data on brownfield sites. We’re currently building and testing several resources to help local planning authorities publish and update their data. Join the conversation on our GitHub issues pages if you’re interested in brownfield site data.

Current areas of investigation

We’re exploring the following areas to help us learn how we can open up brownfield site data and make it easier to use:

In progress

An index of brownfield site registers

Questions we’re asking

Brownfield site data for local authorities can be difficult to locate and there’s no public register where all local authorities’ data can be viewed in one place. Would creating a national index of all brownfield data be of value to local authorities and other interested members of the community?

What we tested

What we learned

We made a number of useful observations while building the index, including that:

  • planning authorities often failed to provide a direct link to the data (for example linking to a policy page instead)
  • when some registers were updated their URLs changed (URLs were not static)
  • registers were often published in formats other than CSV (such as Microsoft Excel files)
  • registers often contained gaps or errors
In progress

Guidance on updating your brownfield site data

Questions we’re asking

Would guidance help local authorities publish their brownfield data to a standard format, and minimise errors?

What we will test

We’re currently creating guidance on publishing brownfield site data. We will test this guidance with users from local planning authorities and continue to improve it.

In progress

Brownfield site data validator

Questions we’re asking

Often the person in the local authority updating the brownfield site data has little or no spare time, has varied responsibilities and is not familiar with the brownfield data format. As a result, errors are common in the published data. Would offering a simple tool for validating a local authorities’ data improve this?

What we will test

We built and tested an early version of a validator and based on what we learnt we are now creating a new validator tool. This validator will check local planning authorities’ brownfield site data and display the results of all local authorities’ data.

In progress

A way of fixing errors

Questions we’re asking

Many of the errors we identified in published brownfield data were common mistakes, such as switching GeoX and GeoY coordinates, or omitting empty rows in the data. Would offering to automatically fix common errors after validating the data be useful to local authorities and improve the quality of the data?

What we will test

What we’ve learned

We spoke with people from local authorities who are responsible for publishing the data. Often they were not technically trained or experienced with working with data. We tested an old version of the validator with some of these users, many of whom were able to spot and correct the data errors. We may work on building a way of automatically correcting errors into the new validator.

Upcoming areas of investigation

We plan to explore the following by prototyping tools and by testing and consulting with people involved with brownfield sites, and responding to your feedback.

We will regularly add updates to the following issues on GitHub:


15 June 2019

We met again with Campaign to Protect Rural England (CPRE) to further understand how they’re using brownfield data and how this might connect to other data sets. We also spoke about our ideas to make it easier for local authorities to collect and publish their data.

June 2019

We’ve been analysing the existing brownfield data to explore whether we can propose a simplified data standard that’ll be easier for local authorities to publish against. As a part of this work we’ve also been looking at what has changed since we last looked at the published registers.

4 April 2019

We met with CPRE to understand more about how they collected the brownfield data, the challenges they faced, and how they used the data.

March 2019

The CPRE published the 2019 State of Brownfield annual report. In the report they highlighted some of the challenges they faced whilst collecting brownfield data.

Summer 2018

We built a register of all the brownfield registers and prototyped a tool to validate the data.

Help us improve Digital Land by sharing your feedback with us.