HOW LOW CAN YOU GO? TESTING THE LIMITS OF SPATIAL AND TEMPORAL RESOLUTION FOR AIRBORNE LIDAR

As high resolution airborne lidar becomes more widely used in the geosciences, it is important to understand what kind of natural and man-made features can be resolved with lidar imagery, and what kind of acquisition specifications are necessary for a particular application. The Oregon Lidar Consortium has funded a large body of very high resolution (8 pulse per square meter), high accuracy (vertical RMSE <6 cm) lidar through the Oregon Department of Geology and Mineral Industries. All of these data have been collected) using the same specifications, practices and equipment. This data set provides an excellent opportunity to test aspects of spatial and temporal resolution of airborne lidar.

We look at three examples where high resolution data sets can be paired with ground observations. The Panther Creek area in the densely forested Oregon Coast Range has been flown four times since 2006. These consecutive lidar flights provide an opportunity to test the concept of improving the ground model in dense vegetation and increasing the spatial resolution in unvegetated areas by combining points from multiple surveys. In the Sandy River canyon, which drains Mt Hood in the Oregon Cascade Range, we test the limits of change detection by examining the differences between four consecutive surveys to determine how small a change in the shape of the ground surface can be detected. In the Ontario area, in the arid Snake River Plain, we test the absolute spatial resolution capability of a single flight of high pulse density airborne lidar in an environment with no vegetation and subtle man-made topographic features like irrigation ditches and plowed fields.