(Digital Surface Model (DSM
In a LiDAR system, pulses of light travel to the ground. They return and are detected by the sensor giving the range (a variable distance) to the Earth. Hence, how they earned their name of Light Detection and Ranging
In the end, LiDAR delivers a massive point cloud filled of varying elevation values. But these elevation values can come from the top of buildings, tree canopy, powerlines and other types of features. A DSM captures the natural and built features on the Earth’s surface
(Digital Elevation Model (DEM
A digital elevation model is a regularly-spaced bare-earth raster grid referenced to a common vertical datum. When you filter out non-ground points such as bridges and roads, you are left with a smooth digital elevation model. The built (powerlines, buildings and towers) and natural (trees and other types of vegetation) aren’t extruding in a DEM
(Digital Terrain Model (DTM
When you refer to this USGS LiDAR Base Specification (on page 28), a digital terrain model (DTM) actually has two definitions depending on where you live
ليست هناك تعليقات:
إرسال تعليق