Map layers for planning application constraints

We could have put constraint layers on the map a long time ago. We held off because the versions we looked at either needed a GIS degree to make sense of, or they slowed the map down, and a map that stalls every time you switch something on is worse than no layer at all.

We wanted them to work the way the rest of Plota does. The work happens before you arrive rather than on your machine, which is why turning a layer on costs you almost nothing and why it works on a phone as well as it works on your desktop.

Every map on Plota now has a Layers button. Press it and you can draw flood zones, listed buildings, conservation areas and 43 other designations straight onto the map you are already looking at. Click anywhere and it names what is there and links to the record it came from.

The layers add context to the application you are looking at. A proposal reads differently once you know the building is Grade II listed, or that a public footpath crosses the site, or that it sits in flood zone 3. Green belt tells you one thing; Metropolitan Open Land tells you the same thing inside a city, which catches people out. An application to turn a yard into flats means something else again once you can see the yard is inside strategic industrial land, where London policy will resist it.

96 datasets, 46 switches

Counting datasets is easy to inflate. We collect 96 published datasets and show 46 switches, because the number of datasets is a measure of our work rather than a measure of what you should have to think about.

The gap between the two numbers is normalising:

• Flood risk is one switch. Zones 2 and 3 are separate datasets and are drawn in separate colours, so the distinction is on the map rather than behind a click.
• Protected wildlife sites is one switch over five registers: special protection areas, special areas of conservation, Ramsar wetlands, and national and local nature reserves. Click one and the card names which of the five you hit.
• Listed buildings is one switch over three countries. Historic England, Cadw and Historic Environment Scotland publish separately, with different column names and different grade wording. We map them onto one shape.

16 of the 46 switches draw on more than one country's register. A boundary between England and Wales is a change of publisher, not a change of what you can see.

Farmland grades, updated 11 September

When this was published, farmland came from the map Natural England surveyed in the 1970s and 80s. It is drawn at 1:250,000, it does not split grade 3 into 3a and 3b, and the towns it leaves blank are the towns as they stood forty years ago, so the shading ran over four decades of housing.

It now comes from three sources. Natural England's post-1988 field surveys are used wherever one exists: 3,576 surveys covering 231,831 hectares. That is roughly 2% of England's farmland, and a much larger share of the land people apply to build on. Everywhere else in England we use the predictive map Defra published in October 2025 and revised in March 2026, which does split 3a from 3b. Wales uses the Welsh Government's predictive map. Today's built-up areas are cut out of both.

The 1970s map stays as its own switch, because it is the one most planning maps still show. Draw both and the disagreements are visible. A field can be grade 2 on the old map and 3b on the new one, and neither of them is a site survey.

Updated 6 October 2026

Seven switches are new, three existing switches draw more than they did, and every layer built from planning.data.gov.uk was rebuilt from October's files. The panel has a new section, Ground, for what lies under a site rather than the policy over it.

Flood and water

Surface water flooding now covers England as well as Wales, from the Environment Agency's map of where rainwater collects when it cannot drain away. It draws once you zoom in to a street. It is a picture rather than a set of outlines, so Check a spot, the emailed report and application pages cannot read it. It is on the map only.

Future flood zones is the Environment Agency's flood map for planning with climate change added: flood zones 2 and 3 grown to where the Agency expects rivers to reach in the 2080s, and the sea with its rise to 2125. Councils use it to decide when a site needs a flood risk assessment and the sequential test. The Agency says it does not show whether a particular property is at risk, and the card says the same. Where the Agency has not drawn the new extent yet, the map marks the area as not mapped rather than leaving it blank. England only.

Flood defences draws the Environment Agency's record of 141,387 walls, embankments, flood gates and stretches of high ground in England, each with the river it protects, the flood it was designed for and its last condition grade. A defence lowers the chance of flooding without removing it, and the flood zones used for planning ignore defences, so land behind one stays in its zone. The Agency has retired its map of areas benefiting from defences and planning authorities have been told to stop using it, so we draw the defences themselves and never say that a site benefits from one.

Ground

Radon is the Indicative Atlas of Radon from the British Geological Survey and the UK Health Security Agency, covering Great Britain and Northern Ireland. Each 1 km square takes the highest class found anywhere inside it, from class 2 (1 to 3% of homes at or above the action level) to class 6 (30% or more). It is indicative: a site can be lower than its square, and only a test measures a building. New buildings and extensions in an affected area can need radon protection under building regulations.

Coal mining shows three datasets from the Mining Remediation Authority, which was the Coal Authority until 2024: the coalfield, the development high risk area inside it, and 162,490 recorded mine shafts and adits, which appear when you zoom in to a street. Most planning applications in the high risk area need a coal mining risk assessment. Positions taken from old plans can be out by several metres, and unrecorded workings can exist anywhere in the coalfield. England, Wales and Scotland.

Heritage and trees

Listed buildings now draw the outline of the building where its council has published one, 130,242 of them, from street level. The outline answers what a dot cannot: whether a site is the listed building or the house next door. A pin inside the outline is the listed building, and a pin outside it is a neighbour, however close it is to the dot. The outline is the council's guide and the list entry is the legal record, and protection can reach beyond the drawn line. England only, where councils publish.

Tree preservation now shows 250,609 single trees named in councils' orders, as dots from street level, with the species where the register gives it. Coverage depends on each council publishing its trees with a location. Application pages and the API name a single tree only within 15 m of an application pinned to the building itself, 15 m being the largest root protection area the British Standard gives a tree.

Land and policy

National infrastructure maps the 285 projects on the Planning Inspectorate's register: the solar and wind farms, power stations, pylon lines, pipelines, roads, railways and reservoirs that a Secretary of State decides under the Planning Act 2008 instead of the council. The card gives each project's stage and the date it reached it, and links to its page. A project at pre-application has no application yet and its boundary is often a wide study area, so application pages list it as context and Check a spot rates it low. England and Wales.

The green belt card now says who decides grey belt. Some green belt land can count as grey belt where it does not strongly serve the green belt's purposes. There is no national grey belt map, and the government has said it will not publish one: the council decides, in its green belt assessment or on each application, so we do not draw one. The card links the government guidance.

London

Protected views draws the 13 protected vistas of the Mayor's London View Management Framework, towards St Paul's Cathedral, the Palace of Westminster and the Tower of London. Each has a landmark viewing corridor, where development above the threshold plane should be refused, and a wider setting around it, where the effect on the view is judged. The layer shows where a view runs; the framework sets how high a building may go. A revised framework is out for consultation until 4 December 2026 and is not yet in force, so the layer follows the adopted one and the cards say so.

Public transport access (PTAL) draws Transport for London's 2023 access level for every 100 m square in London, from 0 (very poor) to 6b (excellent), worked out by TfL from the walk to nearby stops and how often services run in the morning peak. Councils use it to set parking and housing density. The bands are TfL's own, unaltered. Powered by TfL Open Data.

The October refresh

Every layer built from planning.data.gov.uk was rebuilt from files fetched on 5 October. Ten had changed since September: listed buildings, conservation areas, scheduled monuments, ancient woodland, national landscapes, tree preservation, Article 4, Ramsar sites, historic parks and gardens, and brownfield land. Each new file was compared with the one it replaced before it went live.

The new layers are read everywhere the old ones are, apart from surface water: Check a spot and its emailed report, application pages, and the constraints API.

Quick enough to leave switched on

Turn a layer on and it draws straight away. Turn all 46 on and the map still pans. You can work with them on rather than switching them off to get the map back, and whatever you leave on follows you to the next map.

It works on a phone

Every switch works on a phone, in a drawer that opens from the right, so you can stand in front of a building and check whether it is listed and what grade it is. Constraint mapping is normally something you do back at a desk.

One click, one card

One click gathers everything under that point into a single card: the designation, its grade or catchment, and a link to the source record. Where a photograph of a listed building is available from a third party source, the card shows it, which saves checking you have the right building.

All 46