What Is A Topographical Survey?
Read our quick guide on what exactly a topographical land survey is.
Article By: Tom Ayre | Last Update: April 2022
What Is The Purpose Of A Topographical Land Survey?
A topographical land survey accurately measures, and records position and height data for man-made / natural features within a defined survey area. The recorded data is used to create a range of information such as CAD drawings, contour maps, terrain models and more.
Topographical surveys are utilised by a range of professions including architects, engineers, building contractors to effectively visualise, plan and develop their projects. The drawings and information produced by the survey work are used as a base to design from.
A topographical survey is a crucial component of a successful construction or engineering project. Position and height data recorded by the survey can help prevent costly problems such as building in unsuitable areas.
An example of an unsuitable area which could be revealed by the topographic survey include:
- Close to a watercourse / drain and prone to flooding.
- Next to large trees, which may cause issues with ground swell / roots.
- Too close to a boundary, which may cause issues with council permissions.
Another benefit of a commissioning a topographical survey from the start of a project is that it will make the setting out engineer’s job much easier. A topographical survey will leave a number of fixed reference markers on site, such as nails in concrete. These positions can then be utilised when setting out the new design so that elements such as foundations, brickwork, new trees etc are in place in the correct position.
Who Carries Out A Topographical Survey?
A Topographical survey is typically undertaken by a land surveying company who utilise a range of high-tech equipment such as GPS devices, total stations and 3D scanners to accurately and quickly survey areas of land such as fields, woods, marsh, urban areas and more.
The devices used for the survey are very precise and usually require ongoing calibration to ensure their reliability. Modern equipment such as robotic total stations allows surveys to be undertaken by a surveyor without the need for an assistant!
What Information Do Topographical Surveys Gather?
Topographical surveys (sometimes referred to as “topos”) record a range of information on site and are usually referenced back to a national grid co-ordinate system. This allows the surveyed information to be tied in with other mapping products which are also aligned to a national grid system. In the United Kingdom this is dealt with by the Ordnance Survey.
The features of a topographical site survey depend on the client requirements / the complexity of the project. Examples of what information is typically surveyed includes:
- Land heights.
- Tree locations.
- Existing buildings.
- Change in surfaces.
- Boundary locations.
- Overhead power lines
The process in obtaining a topographical survey is simple. The key component when commissioning a topographic land surveying company is to ensure you have a suitable specification for your chosen surveyors to work from. A specification from RICS (Royal Institute of Chartered Surveyors) would be a good place to start. Once you have a specification then carefully choose a surveying company. It is always worth checking reviews, previous work, and insurances to see if they are the right company for your scheme.
What Projects Require a Topographical Survey?
Whether you are building a new house or designing a new railway line, a topographical survey is essential when land is being developed.
Without accurate drawings and design data, it’s difficult to plan a project accurately and safely. The surveyed information allows designers to see exactly how the current site is arranged and includes accurate, co-ordinated positions and associated heights of items.
Without a survey, you may not know about important issues regarding your site that may be costly to fix further along the line. Examples include:
- Building too close to something such as a boundary. Planning might be rejected!
- Building too high from the ground, again, planning may be rejected.
- Developing an area with lots of trees and vegetation. May be too expensive to clear?
- Does the ground level change a lot? Moving earth is expensive, so optimising this early on can help with costs.
Broadly speaking, every construction / engineering project should have some form of survey undertaken before anything is designed. However, in our experience the following types of projects always have a survey undertaken before any design work takes place:
- New build developments.
- Large extensions.
- Large landscaping schemes.
- New / updated drainage.
- Drainage schemes.
- Earth moving projects.
- Dredging / river works.
Key Benefits Of A Topographical Survey
A topographical survey will help you design more effectively and assist in avoiding future problems and making your land as efficient as possible.
- Optimising the positions for what you are designing, such as new buildings and structures.
- Avoiding potential planning application refusals.
- Reduce potential costs by identifying objects that may cause delays in construction.