21
Feb
2014

Behind the scenes: how our surveyors record change

We’re often asked about how our surveyors carry out their work, and particularly how they cope in adverse weather conditions. Our blogging surveyor Dom Turnor, gives his take on surveying in the recent wet weather.

The Telegraph reported at the end of January, that we have had the wettest January since records began over 100 years ago, with some parts of Britain receiving two times the average rainfall for the month. Whilst this has caused devastation and considerable heartache across the country, the job of a field surveyor goes on; we have deadlines to meet and customers to serve and they need new or amended data to appear on our maps so they can go about their business.

Surveyor-rain-1980s

In the not too distant past, the surveyor actually updated the maps using an unwieldy sketching case and sharp pencil, and would shelter underneath the case during spells of rain (see above in the 1980s)! But things have changed dramatically in the last 20 years and exponentially in the last 10 (see Dom today, below). Now when we go out to survey we carry with us a combination laptop/touch-tablet type computer and this has to be tough and durable as we work in all weather – rain, snow, sleet and, thankfully, bright sunshine sometimes. So these rainstorms are a pain but do not constitute an insurmountable problem, we just need to make sure to carry a rag to keep wiping down the screens!

dom-surveyingWe carry these tablets around our shoulders and they are generally coupled via Bluetooth to our highly sensitive Leica GPS units, which we use to pinpoint the position of new features or check the position of existing data on the maps. The GPS units stand about 1.8 metres tall and are extremely accurate giving us a position down to  centimetre variance, and by using the specifically designed programme on the computers we carry we can create a framework of the detail required and bring the map up to date.

But in order to create a point on the map the GPS needs to be able to ‘see’ a certain number of satellites in the sky, otherwise the reading will not be accurate enough and we may receive a rogue point on our data. So, for the measurements we cannot get via GPS, we use a hand held Leica laser measuring instrument, or failing that a good old-fashioned 20 metre tape measure and drag it through the mud. Once we have plotted a number of points onto the map, we begin the task of joining them up to reflect the shapes of what is actually on the ground. The points joined up, we then attribute the lines and shapes within the lines to correspond to what they are, for example public road edge, public road, obstructing feature, private garden, building outline and built structure to name a few. This allows our customers to interrogate the maps for their own means.

Once the field surveyor has created the framework, joined the dots and attributed the lines to reflect what is on the ground then the ‘job’ is sent back to the servers at our Southampton head office where it is incorporated into the master map of Great Britain by the expert teams there, and a little time, later becomes available to the customer.

If you liked Dom’s view on surveying, you can also find more detail in this blog post.

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