Aerial LiDAR and Photogrammetry: Which Makes Sense For Your Construction Project?

Construction is booming. In 2017, there were a total of 210,000 jobs added to the construction industry, garnering optimistic predictions for 2018. Yet this growth also means that competition is intensifying between construction companies, as they attempt to expand into new markets and maintain both stability and growth. To remain competitive, construction companies are going to need to invest in new, more scalable technologies and improve upon metrics such as safety and productivity. Finding the right surveying solution may be the first step.

The Importance of a Surveying Solution in the Construction Industry

It can be difficult to begin a project without the appropriate surveys — and an incorrect survey can cause a project to come to a complete halt. Consequently, it’s understandable that surveying is one of the faster-growing employment areas, with the growth for professional surveyors expected to be 25% through 2020.

When a survey goes well, the construction project goes well; fewer issues emerge and deadlines are met. When a survey goes poorly, a construction company may find itself running into literally uncharted territory, with potentially every aspect of the project being delayed.

All of this emphasizes the importance of finding solutions that provide extremely accurate data quickly. Today that means aerial data collected from an unmanned aerial vehicle (UAV). When it comes to UAV survey data, there are two main technologies available: LiDAR and Photogrammetry. These both have benefits and drawbacks, depending on the type of project, its budget, and the landscape.

Using Aerial LiDAR for Construction

Aerial LiDAR (Light Detection and Ranging) uses a sensor to detect geographic features from above, creating an extremely precise 3D map of the region. Due to the way that the technology works, aerial LiDAR can cut through things such as brush and vegetation, to properly map the ground. This is ideal for environments that have a significant amount of over-growth, as otherwise, the construction company may not be able to plan ahead for the terrain that is there.

The data produced by LiDAR can be imported directly into construction and architectural software solutions, allowing for detailed simulations of the construction build, in addition to improved costing.

That being said, LiDAR does have some downsides. Not only can it cost significantly more than photogrammetry, but it produces images that are not colored on the RGB scale. Consequently, LiDAR maps can be difficult for human eyes to read, as there may be very little distinction between mapped objects besides their physical texture.

LiDAR is best used when precision matters and there may be interruptions between the aerial system and the ground.

Using Photogrammetry for Construction

Photogrammetry involves using data collected from high-resolution cameras to create either a 2D or 3D survey of an area. As photogrammetry relies upon still images, it cannot be used to get past brush or ground cover; if there’s a significant amount of ground cover, photogrammetry won’t be able to map the terrain. However, photogrammetry has two chief advantages: it’s affordable, and it can sometimes be easier to read by human eyes, if not by software.

Photogrammetry is the ideal solution for organizations that are imaging large, clear areas, and environments that have already been developed. Photogrammetry may also be ideal if the colors in a survey matter; if high resolution, colored images of the site are necessary. Some projects have limited budgets — in these cases, photogrammetry may be the only viable solution. For this reason, this type of surveying is also often used for smaller mapping projects. It’s a simple and fast way to get a reasonably accurate survey.

Using Both LiDAR and Photogrammetry

There is nothing to say that you can’t use both LiDAR and photogrammetry if you find that you have a need the benefits of both. LiDAR and photogrammetry can be combined to create 3D models of environments that are also married with high-resolution imagery. This can give you a complete simulation of the environment, including both the dimensions of the environmental features and their textures. Understandably, this is a costly solution — however, it may be ideal for more involved and complex projects.

Which type of aerial surveying is best for your organization? It will depend on the unique needs of your project. LiDAR can easily be ten times the cost of photogrammetry but provides detailed and precise 3D scans of a region, which can potentially help you prevent unnecessary re-work costs. Photogrammetry is a more affordable and older technology, but it also has some limitations: it doesn’t have the resolution or precision of a LiDAR file. In many cases, photogrammetry may be good enough for the project at hand, and there are situations in which LiDAR may be more difficult to interpret by human eyes.

If you want to find out more about drone-based aerial surveying, Aerial LiDAR, and photogrammetry, it’s best to discuss the topic with your surveyor. There are many factors that go into selecting the best solution, and not all of these factors are going to be immediately obvious.

 

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