Urban Myth: LiDAR and Photogrammetry are Redundant

Feb 18, 2020

When it comes to capturing point clouds, it’s not a matter of LiDAR versus photogrammetry, because both have their benefits and drawbacks.

It’s really about which method is most suitable for your particular application.

YellowScan LiDAR point clouds help archaeologists map dense forest cover.

 

At the end of the day, most surveys can benefit from deploying both LiDAR and photogrammetry. The myth is that they are mutually exclusive. They aren’t. “Lidar laser scanning and photogrammetry are outstanding solutions amongst the current technologies” for geomapping, write Atteyeh Natanzi and Iman Zolanvari in a recent issue of GIM International. LiDAR researchers at the School of Civil Engineering at University College Dublin, Nantanzi and Zolanvari are quick to add, “The latest Lidar scanners are able to capture around one million georeferenced points a second in the form of a point cloud.”

Whether we’re talking about mapping of terrain, or laying out plans for urban development, for instance, LiDAR and photogrammetry can be advantageous, particularly when realizing that world population growth in major cities is exploding. And combining both saves time on the field when doing simultaneous collection.

The YellowScan Surveyor LiDAR with integrated RGB camera.


LiDAR and photogrammetry can of course be applied as well to the examination of soil types and layers; and both LiDAR and photogrammetry make a lot of sense for archaeologists who need to parse out the structures and layout on an ancient site. True, LiDAR output takes less capture and process time. LiDAR also tends to produce a sharper point cloud that’s easier to work with. Here is a breakdown of the benefits and drawbacks of LiDAR and photogrammetry:

LiDAR benefits

  • Multiple returns
  • Fast processing
  • Live visualization
  • Information on every point
  • Intensity
  • Direct georeferencing
  • Reconstructs complex and irregular objects, i.e. vegetation & powerlines

LiDAR drawbacks

  • Harder interpretation
  • Heavier payloads
  • Hard to operate reputation

Photogrammetry benefits

  • Denser point clouds
  • Easy to use, easy to process
  • Humanly easy to understand
  • Natural RGB information
  • lightweight, small carrier

Photogrammetry drawbacks

  • Computing power requirements
  • Sensitive to lighting (passive sensor)
  • Requires narrow flight lines to ensure sufficient lateral image overlap
  • Needs rich texture in images–homogenous surfaces (featureless/monochromatic color surfaces) can’t be 3D reconstructed with high precision

When it comes to LiDAR vs photogrammetry, both solutions have unique capabilities, yet you have two of many means to a goal. In our view, working hand in hand would be optimal, and YellowScan offers dual solutions.

Combining LiDAR and Photogrammetry

  • Add RGB information to enrich the LiDAR data
  • Photo interpretation in laser point cloud helps avoid mistakes
  • Dual collection in one flight, optimal way of gathering data

This is the optimal way of gathering data. And visit the YellowScan website for lots of helpful LiDAR info and downloadables.

–Thibaud Capra, Jordan Robert

Latest news
What’s new at YellowScan