Top 5 Things a Good LiDAR Service Provider Won’t Tell You

18 Sep 2017 11:34 AM | Office Manager (Administrator)

Top 5 Things a Good LiDAR Service Provider Won’t Tell You by Michael Frecks, TerraMetrix

You are a client looking at mobile LiDAR for the first time. You are under budget and time constraints and like all projects safety is a major issue. All are handled efficiently with mobile LiDAR under an experienced service provider. But, there is a plethora of information out there about what LiDAR can provide. What do you believe?

      First, a good LiDAR service provider will not tell you LiDAR is a complete picture. LiDAR is line of sight. There can be occlusions and good project planning can reduce the number of gaps in your data. “Boots on the ground traditional surveying cannot safely give you the wealth of information you acquire with LiDAR”, according to Terrametrix President Michael R.  Frecks, “it does allow additional pickup more safely out of the red zone since mission planning allows for 100% LiDAR coverage in the red zone.”

      Second, that you do not need control. Without control points QA/QC is merely checking any potential LiDAR error to itself. Granted there are instances where the LiDAR data is only being used to check relative distances and the final position is of no consequence but that is the exception and not the rule. Survey best practices is to have proven methods in place to check the final position error of a given data set. As examples, good survey practice means you close a horizontal traverse to check the closure error. An open-end traverse leaves questions as to the accuracy of the work and can lead to sleepless nights. Same issue on vertical levels. Best practice is to close the level run back on itself or on a known point to ensure the accuracy of the resulting elevations. The same best practices go for mobile LiDAR. Checks to control points provide a QA/QC check between the LiDAR and control points established with traditional survey methods. The resulting RMS error report verifies the final position of the LiDAR data (as long as the control points were established using solid best practices). One way of thinking about control is to always have redundancy in the QA/QC and is a very important factor when it comes to trusting the data.

     Third, that you need special software to handle or view the data. “It took a long time for the software to catch up with the hardware abilities,” says Frecks. “Today, there are many free viewers that handle LiDAR data well not to mention internet cloud technology to organize and provide easy access to your infrastructure data. Back in 2000, when we first started using LiDAR, there were only a couple of software options and they were labor intensive. They took quite some time to master. Now there are many options within well-known design software which can jump start the gap between field acquisition and design in the office.”

      Fourth, that you can get survey grade data with a GIS grade mobile scan system. “The reverse is true, you can’t smarten up GIS grade data to survey grade accuracy, so if you need survey grade accuracy acquire the LiDAR data with a survey-grade accuracy system to begin with,” said Frecks. The evangelical approach to presenting mobile mapping is done for clients, telling them that this is the next generation of technology. This approach is usually pitched to decision makers such as business owners and high-level project managers. The data is often presented in an oversimplified, visually appealing way, to demonstrate the general idea and profitability, without the complex technical details clients will not find relevant. However, this form of presentation often pays too little attention to the data. A client should always be educated as to the expected accuracy result so they can understand if the data will meet their needs.

      Finally, that mobile LiDAR is a new technology. “I guess that depends on how long you have been in the business,” says Frecks, a veteran professional land surveyor and LiDAR pioneer since 2000. “Mobile LiDAR is a proven technology that has gained a lot of traction in the engineering profession. However, when it gets into the hands of inexperienced users or a less accurate (cheaper) system is used for a survey grade accuracy project requirement is when the technology struggles with issues. I have come across a few projects that were the perfect fit for mobile LiDAR only to learn the client had a bad experience with a former project and will not entertain using mobile LiDAR”. Terrestrial Mobile LiDAR Scanning (TMLS) is a proven powerful tool for civil transportation.

Michael R. Frecks, L.S.
Terrametrix, LLC President

4852 South 133rd Street, Suite 105
Omaha, Nebraska 68137

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