Infrastructure Inventory and Condition Assessment Using Airborne Laser Terrain Mapping and Digital Photography

The combination of airborne laser and digital camera technologies can be used as a cost-effective and efficient means of digital mapping for civil and environmental applications. A framework for the use of these remote-sensing technologies in conjunction with Global Positioning System (GPS) receivers for digital mapping of infrastructure projects is presented. An example of the benefit of airborne laser terrain mapping combined with differential positioning with a GPS is low-altitude, high-speed laser scanning of up to 81 km² (20,000 acres) per day, which achieves an accuracy of 10 cm with reduced operating constraints, such as cloud and vegetation cover, traffic and usage, and time of day. The three-dimensional digital coordinate data are directly loaded into terrain mapping and computer-aided design software. This leads to efficient and error-free data processing and map generation. Conventional topographic surveys are slow, and aerial photogrammetry is limited by operating constraints and time-consuming data processing and interpretation. Examples of recent applications of the system for diverse projects like pipeline networks, power transmission lines, railroad tracks, and freeway interchanges are presented.