Constructing a GIS-based 3D urban model using LiDAR and aerial photographs

摘要

Due to the increasing availability of high-resolution remotely sensedimagery and detailed terrain surface elevation models, urban planners andmunicipal managers can now model and visualize the urban space in threedimensions. The traditional approach to the representation of urban space is 2Dplanimetric maps with building footprints, facilities and road networks.Recently, a number of methods have been developed to represent true 3D urbanmodels. Those include panoramic imaging, Virtual Reality Modeling Language(VRML), and Computer-aided Design (CAD). These methods focus on aestheticrepresentation, but they do not have sufficient spatial query and analyticalcapabilities.This research evaluates the conventional approaches to 3D urban models,and identifies their advantages and limitations; GIS functionalities have beencombined with 3D urban visualization techniques to develop a GIS-based urbanmodeling method; The algorithms and techniques have been explored to deriveurban objects and their attributes from airborne LiDAR and high-resolutionimagery for constructing and visualizing 3D urban models; and 3D urbanmodels for the Texas A&M University (TAMU) campus and downtownHouston have been implemented using the algorithms and techniquesdeveloped in this research. By adding close-range camera images and highresolutionaerial photographs as the texture of urban objects, effect ofphotorealism visualization has been achieved for walk-through and fly-throughanimations.The Texas A&M University campus model and the downtown Houstonmodel have been implemented to offer proof-of-concept, namely, todemonstrate the advantages of the GIS-based approach. These two prototypeapplications show that the GIS-based 3D urban modeling method, by couplingArcGIS and MultiGen-Paradigm Site Builder 3D software, can realize thedesired functionalities in georeferencing, geographical measurements, spatialquery, spatial analysis, and numerical modeling in 3D visual environment.