Читать книгу Climate Impacts on Sustainable Natural Resource Management - Группа авторов - Страница 38

LiDAR is a remote sensing method in which a pulse of light is used to measure distances. The sensor emits a pulse of light to the earth's surface from an airborne or space‐borne laser for measurement. The technique provides a direct means to measure vegetation canopies' structure (Dubayah and Drake 2000). The pulse bounces off the tree canopy materials such as leaves and branches. The reflected energy is collected back at the instrument. Time taken for the pulse between emission, reflection, and recapture by the instrument is recorded. Various structure metrics are computed, analyzed, or modeled. Different LiDAR systems measure vegetation characteristics, mostly high pulse rate, small‐footprint, first‐ or last‐return‐only airborne systems which fly in the lower altitude region. Other systems are large footprint and full‐waveform digitizing that deliver superior vertical details about the vegetation canopy. Dubayah and Drake (2000) and Lefsky et al. (2002) provided a thorough overview of LiDAR application for land surface characterization and forest studies.

LiDAR systems have successfully recovered forest structure characteristics for different vegetation types quickly and directly. The technology has become an indispensable remote sensing tool for mapping forest inventory and structure. It has become popular for making informed decision‐making in forest management practices. LiDAR's ability to measure vertical as well as horizontal canopy structure can provide essential details for fuel estimation and fire behavior modeling. The flow chart in Figure 2.6 displays fusion of LiDAR and satellite data for improved image classification and feature extraction.