Variogram analysis of high spatial resolution remote sensing data: An examination of boreal forest ecosystems

The site-specific Northwestern Ontario Forest Ecosystem Classification (NWO FEC) was adapted to provide a landscape-scale (1:20000) forest ecosystem c lassification for a study area located in the boreal forest of northwestern , Ontario, Canada. High spatial resolution remote sensing data were collect ed at two altitudes (600 m and 1150 m AGL) using the Compact Airborne Spect rographic Imager (CASI). Variogram analyses were performed on these data to determine the nature of spatial dependence of spectral reflectance for sel ected forest ecosystems. It was determined that an optimal size of support for characterizing forest ecosystems, as estimated by the mean ranges of a series of variograms, differed based on the altitude of the remote sensing system, indicating that different ecological units and/or processes are cap tured at these two altitudes. Results imply a linear aggregation of reflect ance when discrete objects are not resolvable. This observation has signifi cant implications for scaling of reflectance data, albeit restricted to a n arrow range of spatial scales.