The method of land surveying is used to calculate the separations and angles between points on the ground. Traditional and digital tools are used by land surveyors to create surveys, data, and maps that depict the features of the Earth’s surface. For projects involving civil engineering and building, this is crucial.
The first recorded land surveys took place in Ancient Egypt, where surveyors split fertile land along the Nile River after yearly flooding, over 3,000 years ago.
Theodolites and robotic total stations are two examples of modern technologies used by land surveyors to precisely map a region. Computer-aided design (CAD), building information modeling (BIM), or geographic information systems (GIS) software can subsequently be used to edit the data that has been gathered. See Surveying Instruments for more details.
Types of Land Survey
Three main categories can be used to categorize land surveys:
- Standard land surveys: Describing borders, figuring out land areas, and so forth.
- Engineering surveys: Ensuring that a building is built in the appropriate location, etc.
- Informational surveys: Used to make charts and maps.
Geodetic or plane surveys are other categories under which land surveys fall:
- Large areas are typically covered by geodetic surveys, and accuracy requires taking the curvature of the Earth into account. Techniques like triangulation and trilateration are needed for these surveys.
- Contrarily, plane surveys ignore the curvature of the Earth’s surface and treat it as a flat plane. These are frequently applied to smaller spaces. Plane geometry and plane trigonometry are necessary methods.
Land Surveying Uses
Ownership boundaries can be established through land surveying. Boundary information is crucial because it influences where roads or structures will be built, aids in resolving disputes over property lines, and facilitates the creation of land maps.
Other typical applications for land surveying include:
- Preliminary investigations and evaluations of the potential construction locations’ environmental impacts.
- Geospatial measurement – Locating the exact site features’ coordinates.
- Setting out – Establishing on-site building lines and road alignments following plans (basically the opposite of surveying).
- Photogrammetry – Making digital photographs of locations.
- Remote sensing – Using satellite imagery to map land use.
- Geomatics – Collecting information and analyzing and interpreting site aspects with GIS.
- Geomechanics – Keeping track of land movement and subsidence caused by construction projects or natural processes.
- Drawing maps and charts in 2D and 3D.
- Hydrographic surveying – Collecting information for constructing canals, dredging projects, nautical maps, oil and gas exploration, underwater mining, finding and recovering lost ships, and other projects.
Land Surveying Techniques
The kind of land survey approach used will depend on the kind of survey being conducted.
Angles can be measured from predetermined stations using a set of connected triangles in triangulation. This method is effective since it reduces the number of measurements required.
To measure the lengths and sides of the triangles that are used in triangulation, trilateration uses electronic distance-measuring equipment to determine angles. This method is frequently applied to locations with rocky terrain or irregular topography to obtain more precise calculations.
The traverse method makes use of a collection of lines with known lengths and distances that are connected by points placed at certain locations. Traverse lines can be opened or closed, and they can be altered to accommodate obstacles, difficult terrain, and other factors. This is frequently employed for the initial analyses of new highways.
The process of leveling involves figuring out how high one level is with another. Establishing a point’s elevation about a datum or establishing a point at a specific elevation concerning a datum are both employed in surveying. Trigonometry can be used to determine the elevation difference between two places.
In radiation, different points are taken at the survey area’s perimeter from a fixed position above a ground site. On the survey sheet, the points are plotted, the distances are measured, and they are then translated to the necessary scale. It is most frequently used in conjunction with methods like traverse and triangulation, as well as with a plane table (a tool that offers a stable and level surface on which to construct drawings, charts, and maps).