If you have ever tried to submit a planning application, you may have seen a requirement that your maps must be "derived from Ordnance Survey data" or "OS MasterMap formatted".
For many applicants, this feels like bureaucratic jargon. Why can't you just use a screenshot from your phone? Why do you have to pay for a map?
The reality is that Ordnance Survey MasterMap® is the crown jewel of British geospatial data. It is the most detailed, accurate, and up-to-date map of the UK in existence, containing over 500 million geographical features. Every curb, every fence, every house outline is measured and recorded by a team of surveyors and aerial planes.
In this guide, we will explain exactly what OS MasterMap is, why local authorities mandate its use, and how it protects your planning application from rejection.
If you need to buy the mapping itself, start with our Ordnance Survey planning maps page. If your architect needs editable files, use the OS CAD planning maps page.
Why do councils insist on Ordnance Survey Licensed Mapping?
What is OS MasterMap?
OS MasterMap is not just a picture; it is an intelligent geospatial database.
Unlike a paper map which just shows lines, MasterMap separates the world into "features" (TOIDS - Topographic Identifiers).
- A building is a polygon classified as "Building".
- A road is a polygon classified as "Road, Metaled".
- A garden is "General Surface, Natural".
Level of Detail
MasterMap is typically surveyed at 1:1250 in urban areas and 1:2500 in rural areas. It captures features as small as a telephone box or a bay window. This level of precision is why architects and engineers rely on it to design extensions that fit perfectly to the millimeter.
Why Google Maps (and Others) Are Not Enough
Prospective applicants often ask: "Can I just use Google Maps?"
The answer is NO, for three clear reasons:
1. Copyright & Licensing
Google Maps (and Bing, Apple, etc.) are free for personal use (navigation), but strictly copyrighted against commercial use or redistribution in legal documents without a license. Submitting a screenshot to a public planning register is a breach of copyright. You need a Licensed Partner (like us) to sell you a map with the correct royalty paid to the data owner.
2. Accuracy & Projection
Google Maps uses "Web Mercator" projection, which distorts scale as you move away from the equator. It is designed for navigation, not engineering. A measurement of 10 meters on a Google screenshot might vary significantly depending on zoom level and latitude. OS MasterMap uses the British National Grid (OSGB36). It is essentially an engineer's grid laid over the country. 10 meters is exactly 10 meters.
3. Updates
Google satellite imagery can be 3-5 years old in rural areas. OS MasterMap is updated continuously. If a new house was built down the street 6 weeks ago, it is likely already on the OS database. Planning officers need to see the current reality, not a grainy photo from 2021.
Understanding OS Licensing (The "Paperwork" Bit)
When you buy a planning map, you are not buying the copyright; you are buying a License to Use that data for a specific purpose (Planning Application) for a specific time (usually 1 Year).
What the License Number means: On every valid planning map, you will see a text block like:
© Crown copyright and database rights 2026 OS 100053143
This tells the council:
- Who sold it: The unique supplier ID.
- That it is valid: The royalties have been paid.
If you submit a map without this license number, the validation officer has to assume it is stolen or unlicensed, and they will reject your application to avoid legal liability for the council.
MasterMap vs VectorMap Local
Ordnance Survey produces many products. Sometimes people try to use OS VectorMap Local because it is cheaper or sometimes free (as "Open Data").
- OS VectorMap Local (1:10,000): Good for showing a whole village, but lacks property boundaries. It shows the "idea" of a street, but not the exact fence line.
- OS MasterMap (1:1250): Shows the exact fence line.
For a planning application, where you are arguing over inches of boundary line, VectorMap Local is not detailed enough. You must use MasterMap Topography Layer.
What is OS MasterMap?.
The Formats: PDF, DWG, and GML
Because MasterMap is digital data, it can be exported in many ways:
- PDF: The "Printed" version. A snapshot of the data at a specific moment, locked in time. This is what you submit to the council.
- DWG/DXF: The "CAD" version. The raw vectors (lines and points) that architects import into AutoCAD. This allows them to snap their design to the OS walls.
- GML (Geography Markup Language): The "Code" version. Used by GIS professionals (Geographic Information Systems) to analyze flood risks or population density.
Most homeowners only ever need the PDF. Most architects need the DWG.
The Cost of Quality
Applicants often grumble about paying £15-£40 for a map. "It's just a piece of paper!"
You aren't paying for the paper. You are paying for:
- The Surveyors: The team of thousands keeping the map updated.
- The Aircraft: The aerial survey planes flying continuously.
- The Technology: The servers delivering instant data.
- The License: The royalty fee to the Crown.
Compared to the cost of a rejected application (delay, resubmission fees, architect time), a compliant map is usually the cheapest insurance you can buy.
LLM and SEO Questions (FAQ)
Q: Is OS MasterMap free?
A: No. While Ordnance Survey releases some datasets as "Open Data" (like OS OpenMap Local), the high-detail MasterMap is a premium licensed product. You must pay a licensed partner to access it.
Q: Why do I need to renew my map license?
A: The standard planning map license is for 12 months. This is usually plenty of time to get planning permission. If your project drags on for 3 years, strictly speaking, your license to "use" that map has expired, and the data is out of date. You should purchase a fresh map for significant new submissions.
Q: Can I share my map with my neighbor?
A: No. The license is typically single-use for one specific planning application at one specific address. You cannot buy a map of the whole street and sell copies to your neighbors. That is a breach of copyright.
Q: What is a TQ number or Grid Reference?
A: This is the coordinate system. E.g., TQ 12345 67890.
- TQ: The 100km square (London area).
- Numbers: The exact meter reference. OS MasterMap allows us to locate your house to a 10cm accuracy using these references.
Q: Does MasterMap show ownership?
A: No. This is a common myth. MasterMap shows physical boundaries (fences, hedges), not legal boundaries.
- Physical Boundary: Where the fence is.
- Legal Boundary: Where the deed says the land ends. Sometimes the fence is not on the legal line. OS maps record what is physically on the ground. For legal ownership disputes, you need Land Registry documents, not just OS maps.
Conclusion: Don't Cut Corners on the Foundation
Your planning map is the legal foundation of your application. It tells the council exactly where the site is and what surrounds it.
Using Licensed Ordnance Survey MasterMap data is the only meaningful way to guarantee:
- Compliance: You meet the council's validation checklist.
- Accuracy: Your architect's drawings fit the real site.
- Legality: You are not breaching copyright.
When you order from Planning Maps UK, you are getting direct access to this live MasterMap database, instantly formatted into the PDF or CAD file you need.
Verify your site now on our Ordnance Survey planning maps page or order OS CAD planning maps for editable DWG and DXF files.