LiDAR (Light Detection and Ranging) is a remote sensing technology that collects information reflected or refracted from the Earth’s surface. The instrumentation that collects LiDAR data can be housed on drones, airplanes, helicopters, or satellites, and consists of a laser scanner that transmits pulses of light. These transmitted pulses reflect or refract from objects on the Earth’s surface or from the surface itself, and the time delay is recorded. Knowing the travel time and the speed of light, an elevation of each pulse above the surface can be determined. From the pulse data collected, the user can determine the topography and landscape features of the Earth or whatever surface has received the pulses. The evolution of software that displays and analyzes LiDAR data and the development of new and more compact file formats have allowed the use of LiDAR to grow dramatically in recent years.
The capture of massive quantities of spatial data, able to be distributed and shared in real time, provide for an ever-increasing range of environmental and societal applications. Data capture includes the principles, methods, technologies, applications, and institutional/programmatic aspects of spatial data acquisition. Sources of data include global navigation satellite systems, satellite and aerial sensing, field surveys, land records, socioeconomic data (e.g., census), volunteered geographic information, wireless sensor networks, and unmanned aerial systems.
Topics in this Knowledge Area are listed thematically below. Existing topics are in regular font and linked directly to their original entries (published in 2006; these contain only Learning Objectives). Entries that have been updated and expanded are in bold. Forthcoming, future topics are italicized.
|History & Trends||Processing Remotely-Sensed Data|
|Changes in Data Capture Methods Over Time||Image Interpretation: Aerial Photography & Satellites|
|Georeferencing and Georectification||Feature Extraction in Satellite Imagery|
|Digital Data Sources & Capture Methods||Ground Verification and Accuracy Assessment|
|Historical (Paper) Maps||Spectral Properties of Terrestrial Surfaces|
|Global Navigation Satellite Systems||Structure from Motion Photogrammetry|
|Mobile Applications||GIS and Surveying|
|Aerial Photography: History & Georeferencing||Professional Land Surveying|
|Ground or Street-Level Imagery||Land records|
|Social Media Platforms||Ocean Surveying|
|Volunteered Geographic Information (VGI)||Field Data Collection|
|Remote Sensing Platforms & Sensors||Sampling: Size Selection, Sample Types, Intervals|
|Remote Sensing Platforms overview||Field Data Capture Technologies|
|Nature of multispectral image data||U.S. Census Data|
|Unmanned Aerial Systems (UAS)||Data Coordinating Organizations|
|Landsat||Multi-Organizational GIS Coordination|
|Light Detection and Ranging (LiDAR)||Federal Agencies & National Organizations and Programs|
|Indoor LiDAR Scanning||International Organizations & Programs|
|Radar, Sonar, and Echolocation|
|Airborne LiDAR Bathymetry|