Lidar vs Photogrammetry: Types of Remote Sensing
As remote sensing technology continues to develop and improve, we’re seeing more uses and opportunities to create value in new industries and fields of study — from environmental science to public safety to telecommunications.
Several different remote sensing methods are available today, and each comes with strengths and limitations. Some will be well suited for one application, but not others. How do you determine which is best for your industry?
In this post, we’ll go over two popular remote sensing technologies — LiDAR and photogrammetry — and discuss some key differences between them.
How does LiDAR work?
LiDAR uses basic physics and geometry to uncover remarkable insights. To do so, it uses the power of a laser directed down toward the earth surface and fired in rapid succession — in most cases, a rate of many thousand pulses per second.
The amount of time it takes for the light to return to the LiDAR source indicates its exact distance. It works like echolocation in bats or submarines, but powered by the incredible speed of light (about 186,000 miles per second, if you’re keeping score at home).
Data generated by LiDAR sensors is collected and pinned to GPS metadata to create a detailed map of the landscape. To produce an accurate picture, data from remote sensing tech is then layered to cross-reference ground points and flag errors and inaccuracies.
A LiDAR instrument typically uses three component pieces to collect data. First, a laser produces light that is used as the measurement medium. Reflected light from the ground is collected by the photodetector sensor and optics, and a GPS receiver documents the exact position of thousands of data points in real time.
4 popular remote sensing use cases for LiDAR
- Augmented reality
- Automated driving
- Hazard assessment on lava flows, landslides, tsunamis, and floods
How does photogrammetry work?
The defining feature of photogrammetry is the use of ultra high resolution aerial photography.
By capturing multiple images over a landscape, a “stereo” version is produced that provides software with differing views of a single focal point (for an example of how this works, look at a nearby object and rotate closing one eye and then the other). This shifting perspective creates scale that is used to create a composite image with accurate, measurable definition.
These photographs can collect enormous amounts of data from huge swaths of land. Like LiDAR, photogrammetry can be used to survey structures or property with incredible accuracy. In addition, this remote surveying method produces a photographic document of on-the-ground conditions that can be used to perform surveillance, track changes in an environment, or to create 3D interactive maps of a property.
5 popular remote sensing use cases for photogrammetry
- Oil & gas
- First response
LiDAR vs Photogrammetry: A 2 Minute Primer
Remote sensing allows people to capture and collect important environmental or structural data faster and more accurately than ever before. Here’s a breakdown on two popular data collection practices:
What is LiDAR?
LiDAR, or light detection ranging, uses points of light to create a detailed map of an object’s position in space. It has been used to power everything from automated driving technology to augmented reality to advanced topographic surveying.
When mounted from a UAV or airplane, LiDAR can be used to directly measure the height and density of land and vegetation below, including detailed data on groundcover and trees. This remote sensing method is valuable for mapping structure, density, and other local characteristics of large land parcels from overhead.
What is photogrammetry?
Photogrammetry uses image overlap and UAV-captured images to produce a robust 3D composite of a region.
By using ultra high resolution image collection, in concert with advanced GPS and mapping software, photogrammetry can produce a fully immersive 3D visual model of the real world.
More than a survey map, this process creates an interactive photographic artifact that can be deployed by environmental agencies, industry, and more.
Popular Use Cases for LiDAR and Photogrammetry
|Mining and geology||✓||✗|
|Oil & Gas||✗||✓|
What else can remote sensing do? Here are some examples in the news from across various industries and disciplines:
- Remote sensing used to estimate lake clarity in China
- Using remote sensing to get the full potential out of grain crops
- Studying penguins without disturbing their habitat
What sets LiDAR and photogrammetry apart?
Both LiDAR and photogrammetry are highly accurate for surveying buildings, infrastructure, and raw land. LiDAR can collect more detailed depth information than photogrammetry, but photogrammetry includes detailed visual information on the environment that is indispensable for many researchers.
When it comes to dollars-and-cents decision making, LiDAR tends to be more costly and more difficult to set up and calibrate — especially when mounted on surveying airplanes and helicopters. Thankfully, the cost of both photogrammetry and LiDAR are dropping thanks to widespread adoption of UAV technology across industries.
Choosing the right data processing solution
Selecting the right approach to mapping is the first step, but finding the right partner for the job is equally important. Aerial Applications has the remote sensing technology and the expertise to create value for you and your customers.
Aerial’s new Mapware photogrammetry software is the best tool for the job, whether you want to map a single building, a dozen oil derricks, a protected wetland, or an entire city. This software suite generates bigger, better 3D maps that are fully cloud accessible for use in the field.