A land survey can be described as the collection and processing of all the relevant digital elevation data to identify the precise coordinates of points at ground level. Find out more in this interesting insight.
A correctly executed land survey process can be an extremely important aspect if you are starting the design of a new building, especially if managed using the BIM methodology. In fact, creating an accurate 3D model of the terrain is among the most important steps before starting the design.
If you need to create the digital model of an intervention plot, the first thing I suggest you do is download a land modeling software as it will certainly speed up the process of modeling your terrain environment with particularly simple and intuitive tools to work with.
If you want to know all the details about the land survey, continue reading the article and explore the meaning, methods, purposes and cost of this important process.
What is a land survey?
The land survey phase can be defined as a measurement technique that allows you to acquire the land profile in digital form with its boundaries, dimensions and the relating satellite imagery of a certain portion of the earth’s surface.
This process is commonly performed by professional surveyors who use specialized tools and equipment (such as GPS, theodolites, prisms, total stations, LiDAR technologies and data processing software) to identify and track the exact coordinates of points on the ground.
When do you need a land survey
The many reasons why you may need to run detailed investigations and surveys across a given territory may be of different kinds. Of course, Land Survey campaigns may result to be very useful in the following cases:
- tracing the foundations of a new construction to the ground, to establish the exact location of the building within the lot;
- identifying the position on the ground of natural or artificial elements, such as rivers, ponds, wells, walls, etc.;
- detecting hidden elements in the subsoil (such as pipes, electrical cables, ducts, underground cavities, etc.), in order to avoid them in the case of excavation or construction works. This will also help verify the presence of easement zones or rights of use on the property held by the companies supplying electricity, gas, etc.;
- assessing compliance with urban planning laws and zoning requirements in the municipal territory;
- splitting a large plot of land to obtain smaller lots;
- buying or selling a house or a plot of land: in the course of a real estate transaction, an accurate survey makes it possible to map the property boundaries in advance, to assess the existence of possible restrictions, define the exact location and size of pre-existing structures, and so on. It’s easy to understand that these few exampes can significantly contribute to reducing the risk of disputes between buyer and seller at later stages.
- update an outdated land survey.
How a land survey works
Normally, a land survey process is developed based on three basic steps:
- Preliminary search: the first phase involves the collection of information and documents that characterize the conditions and the existing boundaries of the area where the survey needs to be carried out. These documents may include drawings, maps, testimental wills, notarial deeds, certificates of origin, constitutions of easements, etc.;
- Field surveys and measurements: in the second phase, the collected information is used to identify the location of any existing property boundaries, or to carry out all the measurements and operations required by the purpose for which the survey campaign is performed;
- Processing and delivery of results: the last phase concerns data analysis and processing and the production of necessary documents, maps and graphical drawings necessary to outline the topographical characteristics of the area.
How to read a land survey
In most cases, the result of the survey process consists of a map, accompanied by a written report, which provides useful information on the boundary lines, zoning, easements and elements present both inside and around the analyzed property.
To correctly read and interpret all the information contained in the map, it is important to carefully study the legend that summarizes the graphic symbols used and describes their meaning. For example, the survey can use icons, graphical signs, and specific symbols to mark boundary lines, access points, elevation, wells, trees, constructions, service lines, and so on. In some cases, acronyms or abbreviations can be used directly to indicate the type and position of these elements.
To understand the orientation and size of the illustration, the drawing also shows:
- a compass-like symbol that helps to easily identify the North direction;
- a graphical scale describing how to calculate the actual measurements from the measurements specified on paper.
What are the three main types of land surveys
The method of detection to be adopted depends on the characteristics of the soil (shape, size, etc.), but also on the purpose for which the survey is intended to be carried out. The three most common types of land survey are:
- the topographic survey: it is used to measure the size of a plot of land, identify its shape, elevation and slope and define the position of natural and artificial elements present on it, such as roads, buildings, fences, ditches, embankments, trees, streams, ponds, canals, etc. The topographic survey is generally carried out before making any changes or improvements on the ground (such as excavation and backfilling works, construction of buildings, addition of elements, interventions on the landscape, etc.). Surveyors use a combination of field equipment and Computer Aided Design (CAD) software to create a plant of the property or, if necessary, produce a 3D model of the site;
- the cadastral survey: consists of identifying the measurements of an object so as to be able to frame it within the network of fiducial points, or a series of reference points defined in a unambiguous, materialized and easily identifiable way. The cadastral survey has the main objective of establishing the boundaries of the real estate properties and is indispensable in the fractionation procedures;
- the importance for the construction design: it serves to define the plan-altimetric characteristics of the lot involved in the design of a new building, and to trace the reference points and indicators that will guide the construction process. The surveyor prepares a sketch showing the exact position of the elements and places physical marks on the ground to guide excavation, construction, etc. This type of survey can also be used to determine the progress of the project and the accuracy of the construction compared to the original design plans.
How much can a land survey cost?
The cost of a land survey varies depending on several factors, so it cannot be defined uniquely. However, we can identify the main elements that influence how the cost is determined, as follows:
- type of survey required: simple boundary detection is less expensive than a detailed topographic survey of an extensive area;
- duration of the the documental research phase: if the search for available historical and public information on the property proves to be difficult, taking more time than expected, the final cost could increase significantly;
- size and shape of the property: if the land plot is very large or extremely steep the survey campaign will certainly be more expensive;
- location and level of accessibility: if the property is located far from pathways or accessibility is limited by the thick vegetation, additional costs may also be added;
- equipment and tools used: compared to traditional tools, major modern digital scanning technologies require higher costs for their use.
To simplify the process, you can also rely on a land modeling software with specific tools and functions that allow you to easily build the land plot digital model from a survey in IFC, DWG or DXF format, from raster images or directly from Google Maps.