JP and I will be living in New Hampshire this summer as we conduct field work for our graduate research projects. I was the first to arrive at the Hubbard Brook Experimental Forest last Thursday evening. The weather forecast through the weekend was rain-free and warm, so I wasted no time and got right to work.
First on my priority list was to complete a total station survey in an area with heavy understory before the leaves were out full. I hope to validate or “truth” the LiDAR-derived DEM we’re using for topographic analysis of our research catchment by comparing relative elevation differences between the DEM and relief data collected via a total station. Dr. Scott Bailey and I set up a sort of grid using pin flags at a site with a variety of features of interest (boulders, pit/mound, a catchment sub-divide, and one of JP’s intensive monitoring sites), then our awesome technician Errin ran around with a prism while I aimed the total station and recorded data.
I will perform at least one more total station survey in the coming week. The next location is a clearing surrounding a rain gauge. The idea is to investigate the performance of the LiDAR over an area with dense canopy and an area free of obstructions. We’re also interested in finding out the scale that LiDAR is able to attain. Can it capture micro-topography exemplified by pits/mounds, boulders, large stumps or fallen tree boles? Or will LiDAR and post-processing smooth these features, creating an even surface incorporating only the within-catchment drainages and features of a similar scale? We shall see…