Written by Will Byrne
Is Lidar a dying technology? Not necessarily. It’s evolving and our industry needs to find the right applications for the technology to optimize its current uses.
Is it the best way to acquire elevation data? Not this point in time. I would argue photogrammetry is the easiest and most cost efficient way of creating elevation data sets. The word “phodar” (or “fodar”), an industry acronym for photogrammetry detection and ranging, has been popping up across the surveying and mapping field. However, this is a misrepresentation of what detection and ranging means in practice. The sensor used for photogrammetry is a camera and does not operate with regard to detection and ranging, unlike with Lidar or Radar technology. So why do people use these terms incorrectly? At a glance, Lidar and photogrammetry point clouds look the same, and not to mention Lidar sounds similar. So, it is easy to see how some might confuse the two ideas.
When determining which datasets to use, you must think of your end goal. Am I doing vegetation analysis? If so, Lidar would be optimal since the data is already classified when the LAS file is created. A manual process for classifying photogrammetric point clouds exists but it is more complicated. Software like Agisoft Photoscan and PIX4D are now adding options to classify the ground, which would allow for point filtering and surface creation.
With recent releases, such as the solid state LeddarTech Vu8 sensor, I predict Lidar will make its way into photographs. Lidar units are becoming smaller and easier to use. Where do i see this technology going? Though Lidar will not substitute the flash, it may work in the same fashion to measure the depth of the sensors surroundings. An extra band added to an RGB image would be a good way to store the elevation information. With all the advances in photogrammetry and drone technologies, we will find the right applications for Lidar. The competition between Lidar and photogrammetry can only be good for the evolution of the industry.
Here is an example of a photgrammetric point cloud created with pictures taken from a drone.