Since the 1990’s, Global Positioning System (GPS) has become a very important tool in the surveyor’s armoury. Prior to its general use, positions and levels to the Ordnance Survey National were established using measurements from trig pillars and Ordnance Survey Bench Marks.
Nowadays, an Ordnance Survey position and level can be measured in minutes using a single survey grade GPS receiver receiving corrections from an Active Network to an overall accuracy of better than ±20mm. Trig Pillars and OS Bench Marks are still used but with caution as they are no longer verified by the OS. These will soon surely become a mere reminder of how surveying was previously carried out.
Along with GPS, there are a number of different types of instrumentation and techniques that can be used when surveying. These include;
Most calculations are now automated utilising specifically designed software which reduces the possibility of errors in each survey.
There are an infinite number of variations on the above, all designed to carry out surveys to a suitable specification in a cost efficient way for the user and their clients. For example, a laser scanner would not be used for a simple boundary survey where only several points of detail are required, but for a complicated bridge structure where the amount of deformation needs to be assessed, the laser scanner would be the perfect tool.
In summary, the advancements in technologies of the past 20-30 years has meant that we can collect accurate information, faster and more reliably. Surveys can be sent to clients in the form of a multitude of deliverables of their choice. The crucial decisions for each project now rest on which equipment to use to collect the appropriate information needed for the client and how best to present that information in its most useable format.
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