14
Jul
2010
0

Wessex Archaeology – mapping the past

You might have read my blog on Wessex Archaeology’s finds at our new head office, describing the Bronze Age Farm that was once on our Southampton site…while chatting with the team, based on the outskirts of Salisbury, I discovered just how much they rely on our data, both on paper and in numerous electronic formats. Talking to Paul Cripps, Geomatics Manager at Wessex Archaeology (WA), I discover that their mapping interests run from historic mapping to OS OpenData and a whole range in between.

Much of WA’s work is spatial, finding out how things relate to each other. From historic buildings to excavations to the marine environment, mapping is fundamental to everything WA do. But they don’t just use it as a backdrop, they add information about their excavations and finds too and attach that to their mapping. I was surprised to find that the historic mapping is not only needed to understand change through time but to ensure the accurate interpretation of aerial photography amongst other things; it is not always easy to work out what is shown in an aerial photograph alone and the feature may not be shown on more modern maps, a second world war bunker on a disused airfield can look very similar to a Roman fort from the air!

Paul explained to me how surveying techniques have changed over the years, “OS Net changed the way WA worked. We’ve gone from using measuring tapes to mark out the locations of digs, to using total stations (tied in to trig points) to using differential GPS units (which had to be set up 4-5 hours before work could start). SmartNet uses the mobile phone network and it only takes 5-10 minutes for us to start surveying and we capture 95% of all work with our Leica SmartNet devices. We still use total stations to survey areas where 3D recording is needed, such as buildings and structures, skeletons in graves and so on, but trenches and all basic features can be accurately captured using SmartNet.

“A lot of people wonder what we’re recording all the time, but initial digging on a site only covers a percentage of the area and you need to accurately map these locations. Basic info can be added onto the GPS unit as you work, then we process it in AutoCad or ArcGIS, attach our full database records to the surveyed features, add modern and historic mapping and have all the information we need in one spatial environment.”

WA have six SmartNet systems and want to invest in more as being able to do everything on site makes life much faster and efficient. Rather than a survey team driving around the country and setting surveys up, now the GPS systems are so simple that archaeologists can do the majority of work themselves after some basic training. This leaves WA’s survey specialists to work on training and standards (and still do some surveying too!).

There are some great examples of WA surveying on their website and loads more pictures of them in action on Flickr too.

9
Jul
2010
0

Exploring our surveying antiques

The prospect of the upcoming move to our new head office has resulted in buzz of increased activity around the building in recent months. Just like when you move house, it’s been a good time to have a bit of a clear out and take stock of what’s been hiding under the proverbial bed or in the attic.

Well, part of that process has included cataloguing the many pieces of antique surveying equipment that have been accrued by Ordnance Survey over the past 200 years. Some of the items have played an historic role in the birth of modern map making in Britain and are irreplaceable.

To understand more about some of this fascinating equipment, I caught up with Ken Lacey, a surveyor by trade who now works in our education team. Ken was kind enough to give me a tour of what is rapidly turning into an Aladdin’s cave of cartographic memorabilia, with two pieces being of particular interest.

Here’s what Ken told me:

Ramsden 18” Theodolite

This beautiful piece of kit was made by Jesse Ramsden and bought by Ordnance Survey in 1795.

It is made to the same pattern as the two larger 36” theodolites, also made by Ramsden, and used for the construction of the Principal Triangulation, the very first national triangulation programme to cover the whole of Great Britain which began in 1791.

The 18" Ramsden Theodolite

The 18″ Ramsden Theodolite

The 18 inches refers to the diameter of the horizontal measuring circle. This circle is where you can read the angle between two points of interest. To read this angle you need to view graduated marks through 3 microscopes.

It was used in 1826 for obtaining the precise direction of the Lough Foyle base line, and from that time at Principle Triangulation stations throughout the British Isles.

This famously included on a platform over the top of the cross on St Paul’s Cathedral in 1849. When you consider that its dimensions are 540x720x550mm and it weights 28kg that is no mean feat!

Newlyn Tide Gauge

Ever wondered how we can give a height of an object above sea level? Think about it, the sea is rising and falling throughout the day, year by year and at certain times of the months and seasons we get a higher tide or a lower tidal point.

To calculate Mean Sea Level Ordnance Survey needed to record all instances over the full range of possible variations. That required at least one year of observations for a reasonable determination, but in practise it was calculated over a number of years. From these observations it was then possible to establish the point of mean sea level and from that then calculate the difference in height from this point to any other fixed location.

The Newlyn Tide Gauge

The Newlyn Tide Gauge

To take all the readings required to calculate Mean Sea Level, you needed a tide gauge. Examples were set up Felixstowe (1913), Newlyn in Cornwall (1915) and Dunbar (1917). Subsequently it was decided to solely rely on the tide gauge at Newlyn, which is the one we’ve got here in Southampton, stored out of use.

It was chosen over the others because it was situated in an area of stable granite rock and because the gauge was perched on the end of a stone pier at the harbour entrance it was exposed to the open Atlantic.

It was not therefore liable to be influenced by the silting up of the estuary or river tide delays, as was the case at the previous gauge at Liverpool.

It worked by recording the rise and fall of the sea with two floats attached by chains. The variations were recorded on paper attached to the rotating drum suspended from its centre.

One of the floats that was attached to the bottom of the gauge

One of the floats that was attached to the bottom of the gauge

Every height measurement in the country has been calculated based on the work of this machine.

Responsibility for the Newlyn Tide Gauge continued to rest with Ordnance Survey who provided a full time observer until 1983 when the station was handed over to the Institute of Oceanographic Sciences.

Why not check out some of our other stories from behind the scenes?

5
Jul
2010
0

The Geograph project – submit your photos!

Sponsored by Ordnance Survey, the Geograph Britain and Ireland project aims to collect geographically representative photographs and information for every square kilometre of Great Britain and Ireland. The project, which has been contributed to by 10 019 users is now made up of 1 935 225 images covering 256 701 grid squares, or 77.4% of the total. That’s a lot of photographs!

According to the site, a good Geograph presents images and information on the main human and physical geographical feature(s) present in any given Ordnance Survey 1km grid square. The images on the Geograph site show towns, cities, streets, buildings, countryside, people, boats, cars and more. They capture the everyday landscape of Great Britain and contribute to a valuable open source project, which is free from commercial exploitation.

The images that follow show the type of photographs that can be submitted.

Geograph contribution - The Stroma sets sail for Lossiemouth

Geograph contribution – The Stroma sets sail for Lossiemouth, by Des Colhoun

The great thing about Geograph is that anyone can get involved. It is intended that people will see it as a game or project and a chance to get out more. Either select an area that has not yet been captured or add to an already populated area with new images. The site shows statistics including a leaderboard to show who has submitted the most photos, so if you’re keen you’ll see exactly how well you’re doing. The current leader has submitted 480 images.

Geograph contribution - The View NNW to the Malvern Hills

Geograph contribution – The View NNW to the Malvern Hills, by Pauline Eccles

If you enjoy photography and would like to get involved with this project then why not log in to see what it’s all about http://www.geograph.org.uk/. There’s still plenty of opportunity to add your own images to this growing database.

1
Jul
2010
0

Photo archive goes live on OS OpenSpace

It’s always great to see geography being used as part of interesting projects, especially when it’s for something we wouldn’t expect.

The National Archives has recently introduced National Archives Labs – an interactive test environment where they are making a range of information freely available. And with the huge amount they look after, geography is an ideal way to display and organise it all.

So, they’ve started using OS OpenSpace – our free online mapping tool – to display a massive inter-war photography collection.

The National Archives history photo finder, using OS OpenSpace

The National Archives history photo finder, using OS OpenSpace

The collection was created by J Dixon-Scott who took 14,000 pictures between 1920 – 1940. It’s a candid portrait of life in the inter-war period showing people, towns and countryside. Some of the shots of people working and at school show how much day-to-day life has really changed. It’s a great historical reference tool and by using mapping to display the shots means it is easy to see how much your local area has changed.

As I said, it’s always good to see how our data is being used and we are keen to see and share more examples. If you’re using OS OpenSpace, or know of someone who is, please let us know!

29
Jun
2010
0

Tryfan stands tall(er)

Last week I wrote about an expedition to resurvey the height of Tryfan using modern GPS technology – the same technology the Ordnance Survey uses to map the country. Well, it was a great success and here is an account from John, Graham and Myrddyn. You can also watch an interview with our very own Mark Greaves on the BBC website.

The morning began dark and grey as we drove into the car park at Ogwen cottage, dark because it was just after 5am and grey because a fine drizzle had fallen on the valley.

Early morning cloud began to clear as they reached the summit

Early morning cloud began to clear as they reached the summit

As we emerged from our vehicles clouds of midges descended for breakfast; this promised to be a hard day.We needn’t have worried though.The team of Mark Greaves (Ordnance Survey), Chris Dearden and Brian Jones (BBC), Alun Pugh (Snowdonia Society), Llion Iwan & Stephen Edwards (CREAD) and Mark Handford (Mountain Guide) and ourselves assembled and set off for the summit.

With only a small stop for a live breakfast broadcast from Chris, we were on the summit for 08.00hr and the equipment was then put in place and data collection commenced.To herald this historic occasion the sun pierced the thick mist and within half-an-hour a wide vista of mountains presented itself and the sun shone from a blue sky.

Suddenly, our spirits lifted.

The three hours of waiting, while the GPS collected data, passed quickly, our attention focussed by radio and television interviews.Finally, with the vigil over, we descended the mountain and then made our way to the Snowdonia Society’s headquarters at Ty Hwll where Mark processed the results.

Graham, John and Mark pose with 'Adam' and 'Eve' at Tryfan's peak.

Graham, John and Mark pose with ‘Adam’ and ‘Eve’ at Tryfan’s peak.

With the local press and BBC now all present the result was announced.Tryfan had confounded its doubters and came in at 917.5m, a couple of metres higher than its current map height!

John Barnard, Myrddyn Phillips and Graham Jackson

25
Jun
2010
0

Visiting the Director General’s House

Vanessa Lawrence, our Director General recently paid a visit to a particularly special building in Southampton. 15 Rockstone Place is near the centre of the city and is now the home of a solicitors firm, but it for many years it had a very close association with Ordnance Survey as the ‘Director General’s House’.

Vanessa at the Director General's House

Vanessa at the Director General’s House

The house was built in 1840, and was one of the last projects of Samuel Toomer, who died in 1842 at the age of only 41. It was originally called Avenue House and for the next 25 years it served as a private residence.

There were several tenants until in 1865 the house was acquired from the Toomer family for the purpose of accommodating the Director General of Ordnance Survey.

Major Henry James (who later became Lt General, Sir Henry James), Director General 1854-75, was the first occupier, and the house was used by all his successors until Sir Duncan A Johnston, Director General from 1899 to 1905. It was during Sir Duncan’s tenure that the decision was taken to stop using the house as the official residence.

dg-house2

By 1900, faced with the need for extra space for an increasing amount of colour printing, and not wishing to find temporary accommodation, the decision was taken to convert the house into offices, which is as it stayed until we moved to our current home on Romsey Road in 1969.

The building remained empty until the mid 1980s and been home to a range of different businesses ever since.

Simon Rhodes, Managing Partner at Trethowans Solicitors which now occupy the building, shows Vanessa a painting of the building.

Simon Rhodes, Managing Partner at Trethowans Solicitors which now occupies the building, shows Vanessa a painting of the building.

With our new head office due to be complete in just a few months it could be easy to lose touch with the past, which is why we’re keen to ensure our long heritage is remembered.

18
Jun
2010
0

Our last summer at Romsey Road

 

Adanac Park from the south

Adanac Park from the south

 

 

Front view of Adanac Park

Front view of Adanac Park

We’re just edging into summer now and I realised that it’s been a couple of months since I took you behind the scenes of our new building at Adanac Park. You can see from the pictures above how things have progressed since March and across the business we’re all starting to find out the important things like where our teams will be sitting and what food and drink options will be available!

There are also mixed feelings for many people as Romsey Road has been Ordnance Survey’s home since the 1960s and we’re now in our final months there. The pictures below show you how this site looked in its early days. If you have any memories of Romsey Road, let us know as we’re gathering stories on our wiki from all our employees, past and present.

 

Work starts on Romsey Road

Work starts on Romsey Road

 

 

Romsey Road in the 1960s

Romsey Road in the 1960s

15
Jun
2010
0

Surveying one of Snowdonia’s highest mountains

Over the past year or so, I’ve been working with a group people who are on a quest to rewrite the map of Great Britain.

John Barnard, Graham Jackson and Myrddyn Phillips have been tirelessly climbing some of the country’s most famous peaks and measuring their heights using state-of-the-art GPS equipment.  In doing so they have helped create mountains where once there were mere hills, and vice versa of course!

Their latest expedition takes them to Snowdonia and one of Wales’ most iconic mountains.

This is their story:

“One of the most spectacular mountains in Snowdonia – Tryfan – may be suffering from delusions of grandeur.  With a 915 metre (3,002 ft) map height, it is close to one of Britain’s historically important benchmark heights, that of 3,000 ft.

Since there is a +/-3 metre (+/-10 ft) margin of uncertainty associated with the surveying method that determined this height (using aerial photographs), it means that Tryfan might not be a 3,000 ft mountain at all.

Tryfan, viewed by many as iconic, rises above the Ogwen Valley, its profile dominating the surroundings.  Its crowning glory is its summit, which comprises two monolithic blocks of rock, known as Adam and Eve. They are separated by just enough daunting space to tempt the occasional “fearless” scrambler to clamber atop and jump from one to the other!

At the summit

At the summit

It is our intention in the latter half of June to resurvey Tryfan and determine if this mountain is in fact over 3,000 ft high. Our surveying activities have stemmed from our quest to improve the accuracy of hill-related data within the Database of British Hills, a database available on the internet which contains details of over 6,500 hills.

It’s also fun to bring an activity based on measurement science into a realm such as hill walking.  Moreover, there is the opportunity to take in the beauty of our much varied upland landscape while awaiting the GPS equipment to gather data!

Gathering data

Gathering data

This project is taking place in conjunction with the Snowdonia Society and also with involvement from Paul Beauchamp and Mark Greaves of Ordnance Survey.

The announcement to resurvey Tryfan was broadcast by the BBC on 15 March, who along with ITV and an independent production group, CREAD, all want to join us at the summit on the day of the survey.

We decided it would be wise to conduct a reconnaissance in order to work out exactly, at our leisure, how we would survey Tryfan!  This would save us time on the actual day of the survey as solutions to any problems would already have been found.

The day of reconnaissance was clear and sunny, but with a biting wind from the North West. We strapped the equipment to one of the blocks, checked that it remained stable and made sure that satellite signals could be received satisfactorily. All we have to do now is repeat this procedure, but this time gathering the minimum of 2 hours of data required for Ordnance Survey verification whilst being filmed doing so.  No pressure there then!

Will Tryfan remain a 3,000 footer?  Keep checking the Ordnance Survey Blog for the answer!

For those interested in ‘The Tryfan Project’ you can now follow its progress on YouTube.

John Barnard, Graham Jackson, Myrddyn Phillips”