What is LIDAR Digital Mapping?
LIDAR is an acronym for light, detection and ranging. It is a technique in remote sensing whereby a laser is used to measure the earth's surface. According to ESRI, the process collects highly accurate latitudinal and longitudinal measurements. The technique is highly useful for making aerial maps and is becoming a good alternative to photogrammetry. LIDAR produces mass point cloud datasets which can be analyzed, visualized and managed by Geographic Information Systems Analysts.
· BENEFITS : There are several reasons why LIDAR data is preferable to photogrammetry or other remote sensing methods. For one thing, LIDAR data is collected at an extremely high sampling rate which ensures extremely accurate results. Moreover since LIDAR uses a laser to collect its data, data can be collected both day and night. Lidar is also ideal for collecting elevation data over densely forested areas which is a huge improvement over photogrammetry which cannot collect accurate elevation data under these conditions.
· How It Works: Most LIDAR data is collected either by airplane or helicopter. LIDAR projects use a laser, a scanner and a GPS. In the process, a laser pulse is emitted toward the ground. Objects on the grounds surface reflect the light back to the scanner. The scanner is able to measure the height of objects on the ground based on how long it takes for the light to be reflected back. This makes LIDAR ideal for measuring the grounds surface, the tops of buildings, trees and other features. The process allows surveyors to determine the height and location of features on the ground.
· Types : There are two types of LIDAR. These are Topographical LIDAR and Bathymetric LIDAR. Topographical LIDAR uses a near-infrared laser. Since a near infrared laser cannot penetrate water, Topographical LIDAR is primarily used to map land based features such as cities, mountains, deserts and plains. Bathymetric LIDAR uses both a near-infrared and a green light laser. This allows the system to measure both elevation and water depth simultaneously. According to Civil Maps, this makes it an ideal technology for measuring coastlines, harbors and river banks.
LIDAR mapping offers a highly accurate digital mapping process. Since it is able to take measurements at night and over water, it is an ideal method for mapping both natural and manmade features. According to the National Oceanic and Atmospheric Administration, LIDAR information is used to "produce more accurate shoreline maps, make digital elevation models for use in geographic information systems, to assist in emergency response operations and in many other applications."