Meet the team: Mark Greaves

Continuing our series to introduce you to the hard-working individuals within OS and showcase the wide variety of work we do, meet Mark Greaves. Mark has been with us for over 30 years and is definitely a fountain of knowledge here at OS! Here, he tells us more about how he keeps OS Net running…

How long have you worked for OS?

I have been at OS over 32 years and within this time held differing roles. I started as a Field Surveyor for 7 years, I then spent 1 year doing a HND in Surveying, 3 years as a Geodetic Surveyor, 1 year studying for an MSc in Engineering Surveying & Geodesy and 17 years as Geodetic Analyst. 

How long have you been in your current role?

I have been a Lead Consultant for Geodesy for almost 4 years. Read More


Is Britain on the move?

OS Maps uses GPS to position you

OS Maps uses GPS to position you

Australia has recently announced a 1.8m shift in its mapping coordinates, to compensate for the country’s 7.5cm shift north each year.  Inevitably the question is why, and could the same thing happen here?

In Australia, the shift is to take into account the growing difference between maps (and the coordinate reference system they’re based on) and the system used by satellite positioning (GPS). It’s a fact that the world is constantly shifting on tectonic plates, but maps (and their users) like fixed coordinates that don’t change. Before GPS, this was simple to achieve as most positioning and mapping was created from fixed ground points in a coordinate reference system tuned to a particular country. In Great Britain our fixed points included the very familiar trig pillars and we have a mapping coordinate reference system called OSGB36 National Grid which is fitted closely to our little bit of the Earth. Tectonic plate movements had little or no impact on the mapping coordinates or fixed points because they all moved “as one” and generally stayed the same shape.  Read More


When GPS fails…could you navigate with a paper map and compass?

OS Maps app

OS Maps app

Most of us are reliant on a GPS in our day to day life – whether it’s following the reassuring voice directing us around a traffic jam or grabbing our phone for a quick check that we’re walking in the right direction in a new city. Many now rely solely on GPS for navigating in the hills too. But what happens when GPS fails? It’s something that walkers near Benbecula are likely to experience next month…

Global Positioning System (GPS) is a satellite-based navigation system owned by the US government. GPS was originally intended for military use, but in the 1980s the government made the system available for civilian use. GPS will work in most weather (although space weather can impact – see our previous blog on solar flares), across the world, 24/7. Something that we all benefit from today.

However, the military can (and do) jam GPS signals for their own priorities, such as military exercises. The communications watchdog Ofcom issued a warning recently about GPS jamming due to take place for periods between 1 and 29 July while aircraft crews train over a military range on Benbecula. In these circumstances, would you be able to navigate? Read More


What is a GPX file?

GPX file sampleIn any discussion of routes, navigation or GPS devices, you have probably seen people mentioning ‘GPX files’. GPX is shorthand for GPS eXchange Format and is a type of file that’s really helpful to anyone who loves the outdoors, and is the most popular way of saving and exchanging routes.

What’s in a GPX file?

You can actually open a GPX file in any text editor, and you’ll get something like the image here. While this looks complex, all most people need to know is that it is a list of precise locations, in order, that make a up a route for walking, running, cycling or any other activity. This route can then be placed on top of a map for printing or following on screen.

Using a GPX file – with a mapping application
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Will the GPS replace the compass?

Guest post by Andrew of Outdoor Look.

compass and gps on a mapFor hundreds, if not thousands of years man has explored his surroundings with a compass and maps. Now we see GPS units and apps for smart phones available a plenty, so has the humble compass had its day? Both have their fans with some seeing the GPS as just the latest ‘boys toy’ with lots of buttons and flashing lights and those who see it as a valuable aid to navigating your route that anyone who is serious about walking and hiking must have with them at all times. I lean towards the compass and map, simply because that is how I was taught, but I can see how technology changes and obviously a GPS unit doesn’t take up as much space, but is one better than the other? Let’s see.

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A beginner’s guide to geocaching

A beginner's guide to geocachingMany of us have fond memories of exciting treasure hunts as children, with Easter eggs and other small treats often the subjects of our searches. These days, though, it’s much more normal to find youngsters glued to their television screens, completing quests of a more virtual nature. Technology has certainly affected the ways in which people explore the world and enjoy themselves, but it’d be wrong to assume that old and new can’t be combined to great effect. Geocaching is a fantastic example of this. Read More


Walking with a GPS

Handheld GPS DeviceA Global Positioning Device or GPS is a very handy tool for walkers who want the security of knowing their exact location. If you’re walking somewhere relatively featureless then a GPS provides the peace of mind that you’re going in the right direction. It will also allow you to give the emergency services your exact location, should you get in a spot of bother and need their support. Read More


Are you a social hiker?

Guest post by Social Hiker Martin Free @InSearchOfCloud

How and why I use Social Hiking

I was always a keen hiker. Mum used to take us youth hostelling as kids and though University I was a very active member of the hiking club there. I took some steps to ‘go pro’ and started down the qualification route for mountain leadership, but rapidly realised that I would be better earning my pounds elsewhere and keeping hiking as a hobby. After finishing University, I kept in touch with my hiking buddies and we got together regularly, certainly throughout my 20s. As for most people, life took over. My career, other activities, relationships etc meant that hiking became something that happened less and less frequently.

In 2009, I bought my first proper smartphone – a HTC Hero. It wasn’t the earliest Android phone, but as the first of my friends to get one, I felt like an early-adopter. Having a smartphone opened up a huge range of opportunities to do other things with it, other than just basic calls and texts.

In 2010, I changed jobs. I had been the ‘Training Manager’ for national government agency, which meant working away from home most of the time. I moved back into an operational role near home, working shifts and sleeping in my own bed every night (or day depending on the shift!). This gave me a lot more time to pick up on old hobbies. I started hiking again. I started running again. In both cases, due to my shift pattern I was doing it on my own, mid-week with my smartphone, I started tracking my activities, both for safety and to see later how much I’d done.

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How do we survey the changing face of Britain?

One of our surveyors at head office

Keeping the master map of Great Britain up-to-date is no easy task and sees thousands of changes a day made to our database. We capture these changes on the ground through our team of 240 surveyors equipped with the latest positioning technology and via Remote Sensing, with both our own Flying Unit and strategic suppliers capturing aerial imagery which is then processed back at head office.

The latest technology makes the task of capturing change on the ground faster than ever before. Our surveyors are usually home-workers and keep the GI data up to date within a set area. They work on a Panasonic Toughbook – a ruggedised convertible notebook computer which serves as both their laptop and data collection tool. It’s both showerproof and dustproof which is essential for a job largely carried out in the great outdoors. It connects wirelessly to their GNSS equipment, electronic total station and hand-held laser rangefinder. It’s also the means for them to connect to head office, arrange and order data for jobs and send data back again.

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