Topographical Survey Previous Project in Ponders End, London
Read about our topographical survey in Ponders End Park, Enfield, North London
Article By: Chris Horton
Last Update: March 2019
Project Duration: August 2018
Location: Ponders End, London
Surveyors: Chris Horton & John Lloyd
In August 2018 THS Concepts were commissioned to complete a full topographical survey of a public recreational space in Ponders End, London.
The area consists of approximately 1,600m² of landscaped park space along the main road through the district. It provides a pedestrian route from a busy bus stop and shopping centre to the large park behind, operating as a recreational zone comprising seating, a water feature and a range of planting.
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As with most of our topographical surveys, it was important to set up a strong and precise control network aligned to OSGB36 before the actual survey commenced. Nails were positioned around the area in 3 strategic positions in order to provide a good survey radius and therefore maximise accuracy. Each of these nails were surveyed using our top Leica Geosystems GPS device to obtain a co-ordinate and height which was transferred across to our total station in order for us to resection to a relatively sufficient level of precision. These nails were then re-surveyed using a Leica TS15 to obtain their respective positions to millimetre accuracy and consequently act as permanent control points for future surveyors to utilise.
Often THS Concepts, or even other surveying firms, are required to re-visit sites like this once the initial survey has been completed to either survey additional data or set out according to construction drawings. Therefore, a small network of reliable site controls will be beneficial to all parties all the way through to project completion.
Once we our permanent control was in place it was necessary to install retrotargets around the site in order to quickly ‘free station’ in a convenient manner. This involves moving the total station to a new and unknown position and re-measuring 2 or 3 targets, thus allowing the device to locate itself.
With all topographical surveys we typically begin in an area and move across the site gradually picking up all relevant details. In this instance, John started in the top corner of the park where the total station could resection using our nail positions and therefore survey retrotargets across the site accurately within the survey radius. The park was particularly busy and it was imperative that the total station was securely locked to a fixed object, in this case a large tree. Keeping the device in a minimal number of locations away from paths ensures the risk of theft or damage is significantly reduced.
With no requirement for specific or uncommon survey data, we surveyed the standard items including kerb lines, surface changes, fence positions, tree sizes and locations and street furniture etc. Our client requested spot heights to 2.5m centres so this was done at the end of the works using a reference line which ensures neatness.
A second visit was required in order for John to pick up all of the survey data required. We always ensure our clients are happy with the drawings we produce and understand that some jobs are larger than others and can’t always be completed in a single day. However, our surveyors relish the opportunity to survey a variety of sites and this particular job turned out to be a pleasant break from the usual residential or rural projects.
All in all this survey was a success and we hope our services will benefit the community of Ponders End as the regeneration of the district continues.
If you are interested in our topographical surveying services, whether private or public, please don’t hesitate to get in touch for a quote!