What is LiDAR & How Is It Used By Surveyors?
Our technically advanced surveyors rely on LiDAR to ensure that they are able to gather important data, revolving around the shape and structure of the Earth’s surface.
It is a hugely popular remote sensing method, consisting of numerous laser beams that use advanced light technology to detect the precise measurements of the surface. This data is then turned into 3D models and detailed maps, which ultimately provide surveyors with extremely helpful information about each area and the characteristics for the location.
Where Have I Heard Of The Term LiDAR?
You may recognise the name LiDAR from your iPhone Pro mobile phones, as one of their in-built features has a LiDAR scanner, meaning that it can create 3D models and images of the surroundings. The Police also use LiDAR integrated technology, as this is featured in speeding guns that are able to track and measure how fast cars are travelling. This is LiDAR being used on a much smaller scale, than the LiDAR scanners that are used by Surveyors, however, they all perform the same purpose of being able to detect in-depth information about the characteristics of objects that are in view.
Why Is It Named LiDAR?
The title is derived from the 1960’s, where the terms Light Detection and Radar merged to become a portmanteau. This was before the term was renamed after ‘Light Detection and Ranging’ to become part of the radar and sonar family, being replaced with an acronym.
How Does LiDAR work?
There are ultimately two types of LiDAR, these are topographic LiDAR and bathymetric LiDAR. Bathymetric LiDAR captures a wide range of hydrographic data underwater, so we will be focusing on Topographic LiDAR, as this is what is heavily used within surveying. LiDAR works in a similar way to Sonar and Radar, but instead with a laser that is launched from the sensor. Once the laser is launched, it bounces back from the area that it hits and this length of time is recorded by the sensor. Afterwards, an equation is formed in order to calculate the time, multiplied by the speed of light which is 300,000km per second and then divided by two (to factor in the return journey).
This figure then shows the distance travelled for each laser beam, bearing in mind that the LIDAR fires thousands of beams simultaneously. The unit of time is then transferred into elevation data that detects the characteristics of the scanned objects, such as shape, height and depth.
LiDAR In Topographical Surveying
LiDAR is proven highly beneficial in topographical surveying as it allows for surveyors to be provided with in depth 3D data that they can then use for mapping different areas with precision and reliability. Surveyors rely on LiDAR as it provides them with accurate information at day and night time, allowing them to collect significant information in a short amount of time. LiDAR is extremely precise because of this, being able to detect over a thousand different pieces of data. For example, small and thin products that may not be picked up on usual surveying devices, such as pipelines, are picked up every time by LiDAR scanners.
At Merrett Survey, our topographical surveyors conduct LiDAR surveys based on your independent needs and requirements. We usually use LiDAR primarily for rural urban areas, such as in telecommunications. However, we also use LiDAR surveys for coastal zone surveys, where data can also be provided for key issues, such as erosion, sedimentation and sea defence work.
LiDAR Surveying Backdraws
A key benefit to LiDAR is that the surface data that is collected through the point cloud detects such large volumes of information that creates highly accurate and visual 3D models. However, even though there are many positives to LiDAR technology, there are also a few limitations. For example, when the system is used for small projects, it can be much more expensive than if the system was used for larger projects. Another drawback that could limit the effectiveness of LiDAR, is that heavy rain can interfere with the laser beams meaning that they are directed back into a different direction and therefore, don’t provide as accurate results. Though these are important factors to consider, LiDAR is still a key system that allows you to see incredible results that your eyes and cameras cannot.
Require a LiDAR Survey? Contact Merrett Survey
If you are looking into a full LiDAR survey or any of the services associated with this article, please contact us by phone, email, or contact form today. A member of our friendly team will be happy to discuss your project and advise on the best course of action.
If you would like to learn more about LiDAR scanning, dimensional building surveys, and topographical surveying, then be sure to visit our news page often to keep track of breaking events in the industry.
Peter Merrett - Owner & CEO
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