LIDAR technologies play a crucial role in the development of high-resolution topographic maps and digital terrain models. Present LIDAR Mapping systems essentially paint the surface with a near infrared laser beam, collecting a dense cluster of elevation points with accuracies on the order of 15 centimeters and greater. In maintaining such vertical accuracies the user is left with reflectance images that contain the elevations of the background natural terrain and everything from vegetation cover (trees & shrubs) to man-made features (roads, bridges, building footprints, utility structures, cars and trucks). LIDAR Mapping data processing provides a unique challenge in the identification, delineation and removal of cultural and vegetation surface features, for the purposes of generating highly accurate bare earth digital terrain surfaces.
Recent trends in mapping by using LIDAR and Digital Camera Systems
Presently most commercial LIDAR applications have focused on supporting the generation of two-dimensional data sets (surface generation for the development of digital orthophotography and the generation of digital contours). Most commercially available software is overwhelmed by the large volumes of data generated by LIDAR Mapping systems, and by its complex data processing requirements. Little attention has been paid to the extraction of digital elevations outside the context of a bare earth surface. Thus a whole set of surface features that include cultural and vegetation cover elevations are being treated more as a nuisance than legitimate 3-D digital elevation features. Our experience has shown us that LIDAR Mapping data processing and analysis is a function of the following factors:
-Terrain Roughness
-Flat to mountainous terrains
-Types of Earth Surface Features
-Natural features (water bodies, vegetation, and geomorphology)
-Cultural Features (buildings, roads, utility structures, ditches, etc.)
-Vegetation Density
-Low to high-density vegetation
-Mixed Terrain and Surface Features
-Heavily vegetated mountains
-Vegetated rolling terrain
-Urban areas
-Spatial Resolution of the LIDAR data
-Point spacing and resolution
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