How Does LiDAR Save Money?

Today, the entire process of airborne laser mapping is highly automated, from flight planning to data acquisition to the generation of digital terrain models.

Airborne laser mapping instruments are active sensor systems, as opposed to passive imagery such as cameras. Consequently, they offer unique capabilities and benefits compared to traditional photogrammetry.

The absolute accuracy of the elevation data is 15 centimeters; relative accuracy can be less than 5 cm. Absolute accuracy of the XY data is dependent on operating parameters such as flight altitude, but accuracy in the range of tens of centimeters to one meter can usually be achieved. The elevation data is generated at thousands of points per second, resulting in elevation point densities far greater than traditional ground survey methods. One hour of data collection can result in over 10,000,000 individually geo-referenced elevation points.

With these high sampling rates, it is possible to rapidly complete a large topographic survey and still generate DTMs with a grid spacing of one meter or less. But accuracy is not the only benefit of airborne laser mapping. The technology allows for extremely rapid rates of topographic data collection, resulting in exceptionally fast data delivery.

As the old commercials used to ask, "Now how much would you pay?"

But wait … LiDAR outperforms traditional photogrammetry in these other areas:

• LiDAR sensors can be operated in any weather and at low sun angles that would prevent an aerial photography survey.
• Rural and remote areas can be surveyed easily and quickly because each XYZ point is individually geo-referenced, and aerial triangulation or orthorectification of data is not required.
• Photogrammetric methods for DTM generation are very time consuming and labor intensive compared to airborne laser mapping.
• While satisfactory results in zones with limited contrast, such as coasts, beaches, and wetlands, are difficult to achieve with traditional photogrammetry, lidar genare traditional generally gives good results in these areas.
• LiDAR performs well in forest areas where vegetation cover prevents visibility of the ground in aerial photographs.
• LiDAR is better for road, pipeline, or power line planning for narrow corridor mapping.
• LiDAR works well for open-pit mining operations where the final data is needed within a few hours of collection.