Wide-area topographic mapping and applications using airborne light detection and ranging (LIDAR) technology

Although the technology has been around a few years now, there are still only a small number of firms i n the world that manufacture airborne light detection and ranging (LIDAR) system technology. A somewhat larger number of firms provide airborne LIDAR mapping services based on this technology (Wehr, A. and Lohr, U. 1999a). Yet, to date, tens of thousands of square kilometers of LIDAR data have been acquired in the United States and other countries for research, feasibility studies and actual applications projects. The reason why so many miles of data have been collected may have to do with the data's flexibility and value. It i s more likely that the reason so many miles are being collected is that the number of applications and uses for the data are growing exponentially. For most applications, LIDAR data does not replace the work of the surveyor or photogrammetrist, but wide-area LIDAR is beneficial for information on thousands of square kilometers and accepted by clients as both economical and accurate. Users are requesting the development of a variety of valueadded LIDAR data products such as bare earth DTMS, geomorphic-structure mapping, building renderings, mathematical model integration, vegetation parameters, change detection and others. LIDAR data are being enhanced with the integration of other data sets, including spectral, hyperspectral and panchromatic imagery, Geographic Information System (GIs) data and mathematical model integration. LIDAR sensors are being integrated with digital cameras, spectral and hyperspectral scanners, and thermal imagers. The sensors also are being upgraded so that scientists can better acquire and analyze such parameters as the returning pulse waveform (frequency shifts) and amplitude. Algorithm development is resulting in software used to create orthorectified imagery (satellite, aerial photography and digital-camera imagery) using LIDAR elevation data. Wide-area LIDAR data collection rapidly is becoming the standard and preferred data set for specific earth science and engineering applications.