A topographical survey is a collection of site data which shows the layout and levels of an area of land. Typical detail would include boundary positions and types, footpaths, walls, service covers, steps and other level changes, building positions, tree locations and many other features which make up the site topography. Most modern topographical surveys are now rotated to fit GPS co-ordinates which shows the location to national grid.
Typically this data is then produced as a finished drawing in AutoCAD which can then have building designs added. Below is an example of what a finished survey should look like
Are there different types of topographical survey?
The majority of our survey requests are for the full detail though some clients may ask for just the boundary of a site. Surveys are produced in either 2D or 3D. The 3D drawing includes the Z value (level) of the point which can be helpful should a designer or architect be using different kinds of software to produce models
How do you go about surveying a plot of land?
Upon arrival on site, the survey engineer will look over the area to determine the best place to put the control, this tends to be several nails put in places to be able to see the detail to collect.
The next stage is to set up a theodolite over these control points and reference the other control stations. Once set up the surveyor will then move around the area collecting data using a staff, the theodolite records this data. This is then repeated on each point until the surveyor has all the data required from the site.
The data on the theodolite is then loaded into the software in the office which produces a rough topographical survey. The surveyor will now modify the data to create a finished drawing which is then exported into AutoCAD to send to the client.
How long does a survey take?
The time to complete a survey depends on its size and detail and so varies from site to site. Areas that are heavily overgrown or very wooded do tend to take more time due to the added detail and trickier points to get and often require another man to operate the theodolite while the lead surveyor moves to get the points
Generally for a domestic property you would expect the site survey to take a day onsite (unless very large or heavily overgrown) and a few hours in the office to create the final drawing
What are topographical survey used for?
The majority of surveys are used to give a designer or architect a base plan to then create the design that their client wants. Other uses could be to check boundary positions, take volumes or soil mounds or buildings or as a base to undertake a tree survey for conservation purposes
Is there any special equipment used?
Any modern surveying firm should be using a theodolite to undertake a topographical survey. A theodolite is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. All angles and distances are stored on a memory card within the unit which can be downloaded back in the office. The most common brands of theodolite include Leica, Topcon and Trimble, we are currently using Leica models
How much does it cost?
The cost of a topographical survey varies due to the different factors of each site such as size, amount of detail, amount of scrub, travel time, access issues and safety. Typically most firms will be able to provide you with a quotation before undertaking the work which will detail the final cost.
The best way to obtain a quote is to send an outline of the area where you want the topographical survey along with any specifications required. Occasionally a site visit maybe required to produce a quote but with rising detail from companies like Google Maps the majority of our quotes can now be done from the office.
Who are your most regular customers?
The most common customer we get are either referrals from architectural firms who we have worked with for many years or from building companies who will go on to develop the land.
We also get a few first-time developers who are thinking about taking their first steps into property development.