New building height data released

Customers of our OS MasterMap Topography Layer can now access  information on the heights of almost 20 million buildings across Great Britain with the alpha release of our building height attributes. Released on 17 March, OS MasterMap Topography Layer – Building Height Attribute is a product enhancement to OS MasterMap Topography Layer, and available to licence holders at no additional cost.

SBH_on OSMM plain

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Enter our piers quiz

If you’ve been entertaining your family over the half term break, it’s always possible that you’ve been to one of Britain’s seaside resorts and taken a stroll along a pier recently. These structures, often known as pleasure piers, started appearing in the 1800s, once the railway network brought mass tourism to the seaside resorts. Due to tidal ranges at certain resorts, the sea wasn’t always visible and the pier enabled tourists to walk out over the sea even if the tide was out (although no pier seemed long enough to account for the tidal range at Weston-super-Mare when I was a child).

According to Wikipedia, the world’s longest pleasure pier is here in Britain, at Southend-on-sea, and extending some 1.3 miles into the Thames Estuary. It can’t compete with the world’s longest pier in Mexico though. The town of Progreso sits on a limestone shelf that drops away gradually as it gets further out to sea. As a result, when they built a pier to allow cruise ships to dock here, it had to be long – over 4 miles long in fact.

Piers in Britain form a part of the 450 million features in our detailed master map of Great Britain. So, we dug into our database and came up with eight examples of piers for you to identify. Post your answers on our blog and claim the glory as an expert pier identifier. Continue reading “Enter our piers quiz”

Eight new things from Ordnance Survey in 2013

We’ve had a busy 2013 so far and there have been a number of new Ordnance Survey products and services released. We thought we’d give you a round-up of our eight  great new and updated products and services of 2013 so far.

OS MapFinder for iOS devices

Our OS MapFinder app for iOS devices launched in January, providing a free-to-download navigation app for walkers, cyclists and more. With over 120,000 downloads of the app in three months, it’s proved very popular and thousands more have downloaded map tiles for the areas they want to explore. We’re currently working on an Android version of the app and we’ll let you know when that’s available. In the meantime, find out more about OS MapFinder for iOS.

Building on the success of OS MapFinder, we recently launched the OS OpenSpace SDK for iOS. Through the new software development kit (SDK), developers can quickly and easily add detailed Ordnance Survey maps to their applications on iPhone, iPad and iPod Touch. The powerful and fast SDK provides a number of significant benefits for both the developer and the end users, including quick rendering and offline mapping, meaning that apps can still function even without a mobile signal. Get started on our website.

Continuing the open theme, we released OS Terrain 50 in April, adding to our OS OpenData product portfolio. Users and developers can now access a new fully maintained analytical height product called OS Terrain 50, available in grid and contour format. You can view and download the product on our website.

In June OS Terrain 5 joined our new height portfolio. Offering maintained national coverage and available in both grid and contour formats, OS Terrain 5 depicts the shape of Great Britain’s landscape. Presented as a Digital Terrain Model (DTM), OS Terrain 5 adds the third dimension to analytical applications such as flood risk assessment and infrastructure development.

We launch the next iteration of our Linked Data service in June at: The improved service is easy to use and access, adhering to new standards and making the data more open.

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Enter our map quiz…on prisons

For years secret military bases were ‘hidden’ from Ordnance Survey maps for fear of espionage and national security. In a similar vein, the internal layout of HM Prison facilities were omitted on the commercially available maps, only showing the outline of the area. But, with the arrival of readily available aerial imagery and web mapping, it was decided to reverse that policy.

See the example below of HMP Dartmoor in the early 1990s.

Although prisons weren’t displayed on our maps in the past, our surveyors and cartographers still needed to capture the detail of the buildings, as they do today. We have 250 surveyors and they work in tandem with our Flying Unit to capture all the changes to buildings, road networks and the landscape across Great Britain.

Now that the map data is readily available, we have eight extracts of OS MasterMap below showing prisons across Great Britain. Can you name them? Post your answers on the blog and we’ll let you know the answers later.

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Name that school – on a map

It’s that time of year when many children and parents (and teachers!) are looking towards the summer holidays. And while those spending time in a school will think they know it insider-out – would they recognise it on a map? Changes to school buildings form a part of the 5,000 changes a day Ordnance Survey capture as we maintain the master map of Great Britain.

We’ve also recently launched OS MasterMap Sites Layer, which provides customers with an easy way to identify an extent that includes all the real-world features that form part of the function of that school on a map. For example, the extent of a school is most commonly made up of buildings, playing fields and associated car parks. You can find out more about it here.

Some schools have been in use for a very long time and are also in historic buildings and popular locations, making them a little easier to spot. We’ve picked eight well-known public schools in Great Britain, using OS MasterMap. Can you name the schools? Post your answers on the blog and we’ll let you know the correct answers later.

Continue reading “Name that school – on a map”

We’ve launched OS MasterMap Sites Layer

We are excited to launch the latest product in the OS MasterMap family, Sites Layer.

OS MasterMap Sites Layer is a nationally maintained dataset that maps the detailed extent of important locations such as airports, schools, hospitals, ports, utility and infrastructure sites and more. The points of access into these sites from the nearest road network are also provided.

This initial release of OS MasterMap Sites Layer focuses on sites in the following themes: Air Transport (such as airports, heliports and airfields), Education (such as schools and university campuses), Medical Care (such as medical care centres, hospices and hospitals), Rail Transport (such as railway station, tram station, vehicular rail terminal), Road Transport (such as coach station, bus station, road user services), Water Transport (such as ports, vehicular and passenger ferry terminals), Utility and Industrial (such as oil terminal, chemical works, oil and gas distribution or storage).

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After the floods – putting Cumbria back together

For the last in our series of posts this week celebrating the Lake District National Park we’re looking at how Cumbria is returning to normal after the floods of November 2009.

The day of 19 November 2009 will remain in the memories of those living in Cumbria, and in particular Cockermouth for some time to come. Heavy rains had caused the rivers Derwent and Cocker, which both meet in Cockermouth, to rise and burst their banks. It was the time it took for the waters to take over the town that caught many unawares and unprepared. By midday the water levels were high, but Main Street was dry, by 3pm the water was a foot deep on Main Street and by midnight Main Street and some of it’s side streets had been transformed into a raging torrent of water which reached up to 8ft deep in places. I’d watched the footage on the television and thought that it looked bad – but it wasn’t until I visited Cockermouth earlier this year that I realised just how bad it had been.

Many bridges, like this one at Little Braithwaite, were destroyed during the floods.

Many bridges, like this one at Little Braithwaite, were destroyed during the floods.

Cockermouth wasn’t the only place affected by the floods. Workington, at the mouth of the River Derwent, was also badly affected with flood water. Being down stream from where the two flooded rivers met in Cockermouth, the flood waters came rushing downstream and engulfed Workington. The wall of water took out several bridges in the town – leaving only the railway bridge left as the river crossing, effectively cutting the town in two. Continue reading “After the floods – putting Cumbria back together”

Lake District National Park – relying on geography

This week we're celebrating 60 years of the Lake District National Park.

This week we're celebrating 60 years of the Lake District National Park.

This week we’re celebrating the 60th anniversary of the Lake District National Park. Today we’re looking at the national park authority and how they rely on Ordnance Survey mapping data. Today we’re talking to Rosemary Long who is a GIS Officer for the Lake District National Park (LDNP). Rosemary has worked for LDNP for over ten years but has been in her current role since March 2011.

What’s a typical day like for you Rosemary?
No two days here are ever the same in the GIS team. The one constant thing that we have to deal with though is location. When we need to show someone where something is in the Lake District the best way is to show them on a map – and the best maps of the Lake District are Ordnance Survey ones. Continue reading “Lake District National Park – relying on geography”

Mapping the changing face of Britain

There isn’t a single part of Britain that doesn’t see some change to its geography. From bustling city centre to wind-swept moorland, change is everywhere. And to help illustrate the fact, we’ve made this short film that shows the cumulative changes made to the OS MasterMap database, the nation’s 21st century geographic Doomsday Book, which is updated around 5,000 times every day.

The video shows an 18 month period in which you’ll see there isn’t a single part of the country that hasn’t been updated. That’s a lot of change.

And if you want to learn more about how we map change, have a read about our Remote Sensing team, a day in the life of a surveyor or the work of our Flying Unit.

You might also like this visualisation showing 7 years of change in Swindon – it’s pretty incredible.

Meet our Remote Sensing team


Last week we heard from the Flying Unit in our Remote Sensing team and this week we’re going to find out what happens to the images the Flying Unit send back to head office. As we capture around 50 000 aerial images of Great Britain every year, we need a team ready and waiting to process that information.

Working at a 3D workstation

Working at a 3D workstation

The Remote Sensing team take the imagery sent through by the Flying Unit and use it to update our large scale topographic database as well as populating products such as Land-Form PROFILE Plus and OS MasterMap Imagery Layer. We actually use the aerial photography to provide three key things:

 • grid coordinates of features on the ground;

 • heights of features and topography; and

 • rectified photography.


Remote Sensing are split into sub-teams to manage these tasks. In Aerial Triangulation, simply put, they ‘pin’ the imagery to the National Grid and ensures that it is positionally accurate. Meanwhile Orthorectification use stereo imagery to assess changes in scale across the photography and produce a combined image which is geographically accurate. This becomes the OS MasterMap Imagery Layer and can be overlaid with other elements of OS MasterMap too. Finally, Data Capture use the stereo photography to measure height and location in order to update our topographic database. Imagery is viewed on a monitor using polarised spectacles to view two images virtually simultaneously.

So that was Remote Sensing 101 and you should have a rough idea of what the team do. I caught up with Jon, Peter and Nicholas to get their perspectives on their roles and discover how things have changed during their time in the team.

Jon has spent two periods of time in Remote Sensing and seen a number of changes between those two times. Part of Jon’s role is working on ‘knitting’ images together. If you think that the cameras on the aircraft are taking hundreds and thousands of images, then you need to find a way to stitch those images together to create one vast seamless image of Great Britain. The images need to be joined in a sensible means – you wouldn’t want a join across a feature such as a house or bridge for example. So Jon works with images, creating the joins and avoiding features, cutting around buildings and so on. Jon told me, “It’s known as seam lining and is especially challenging in built-up areas with large numbers of features and tall buildings creating shadows. It’s ideal to be working on somewhere like Norfolk – which is flat and relatively easy to do!”  

Using the glasses to view in 3D

Using the glasses to view in 3D

Watching Jon and his colleagues work, my first observation, was apparently a very common one “doesn’t it strain your eyes working in 3D?” Jon assures me this isn’t the case, it’s more about relaxing your eyes and looking into the distance – much like with those 3D hidden image posters that were popular in the late 1990s.


I also wondered whether it had been more challenging for the team to move to our new head office. Jon said, “Now that we all work on PCs, we’re not that different to the rest of the building, so the move was quite simple. We just needed blinds up at the windows to make sure we could complete our screen work without any glare. Before PCs, when we had specialist equipment we needed reinforced floors to hold it all – and they had to be sprung to remove the vibrations from all of the equipment.


“We do have a different set up to most of the business as we work from two screens, with one in 3D. But other than the desks, we’re really not that different.”


Peter and Nicholas work on stereo plotting – making sure that things are in the right place in the simplest terms. They can be working on a variety of mapping scales ranging from urban sweep to mountain and moorland. They also undertake areas where it would be dangerous or access would be denied to our field surveyors, such as airports, refineries, railways, new motorways and so on.


Although my initial thought was that it must be great to have a rural area to check as there’s less change to identify, Peter pointed out that if you have a 5km by 5km area of Ben Nevis, you still have to check every section of it and be able to hunt out the smallest change.


Nicholas told me that he has seen many changes during his time in the team – and later this year the editing system will be changing again. “I undertook two months of training outside Remote Sensing before moving into the team. The analogue stereo plotting machines like the A8 and A10 took a long time to set up as you needed to recreate the position of the aircraft as it took each image. The current set up is more of a ‘trick of the brain’ using the dark glasses to create a 3D image on the screen rather than setting equipment up and looking through optics.”


Peter remembered the introduction of digital workstations around 2002. The digital photogrammetrical workstation (DPW) allowed for an on-screen display by which you could view imagery in 3D using special glasses. Peter also recalled the changeover to colour photography around five years ago and the switch to digital cameras. These have allowed the flying season to be extended, as he said “There have been many changes in Remote Sensing as it constantly evolves…we are now moving forward with a new system and I’m sure we will move on to greater and better things.”

Having a quick look through the specs that these guys work on, I have great admiration for the level of concentration required on a daily basis. I only wish I could show you the world as they see it – maybe once we have 3D computer screens as standard, I’ll do just that.