%0 Journal Article
%J International Journal of Remote Sensing
%D 1998
%T Seasonal changes in fractal landscape surface roughness estimated from airborne laser altimetry data
%A Pachepsky, Y. A.
%A J. Ritchie
%K article
%K articles
%K fractal geometry, remote sensing
%K JORNEX, remote sensing
%K journal
%K journals
%K landscape, surface roughness
%K laser altimetry, surface roughness
%K remote sensing, airborne laser altimetry
%K remote sensing, fractal geometry
%K remote sensing, JORNEX
%K remote sensing, surface roughness
%K technique, airborne laser altimetry
%K technique, remote sensing
%K water balance, remote sensing
%X Fractal geometry is a useful tool for the analysis of landscape data. In this study fractal scaling was applied to high-resolution landscape data collected with a profiling laser altimeter. The objective of this work was to assess the persistence of scaling differences over time. Data were collected at the United States Department of Agriculture (USDA), Agriculture Research Service (ARS) Jornada Experimental Range in New Mexico, USA in May and September 1995 and February 1996 over a grass-dominated site, a shrub-dominated site, and a transitional area between shrub- and grass-dominated sites along four transects at each site for each data. Root-mean-square (RMS) roughness was scale-dependent and had more than one range of self-affine scaling. Different numbers of self-affine scaling intervals, boundaries of intervals, and fractal dimensions over these intervals were associated with different land covers. A linearity measure was applied to find intervals of fractal scaling. The number and boundaries of fractal scaling intervals appeared to be persistent over the year. Grass sand shrub sites had two and four linearity intervals respectively. The transitional site had a pattern of scaling that was intermediate between grass and shrub sites. The lowest fractal dimensions at small scales of 6-30 m corresponded to the maximum vegetation in September.
%B International Journal of Remote Sensing
%V 19
%P 2509-2516
%8 1998
%G eng
%L 00764
%) In File (05/07/01)
%F 1132
%0 Journal Article
%J Remote Sensing of Environment
%D 1997
%T Fractal modeling of airborne laser altimetry data
%A Pachepsky, Yakov
%A J. Ritchie
%A Gimenex, Daniel
%K article
%K articles
%K JORNEX, remote sensing
%K journal
%K journals
%K landscape, surface roughness
%K laser altimetry, surface roughness
%K remote sensing, airborne laser altimetry
%K remote sensing, JORNEX
%K remote sensing, surface roughness
%K technique, airborne laser altimetry
%K technique, remote sensing
%K water balance, remote sensing
%X Airborne laser altimetry is a remote sensing technique that can provide high resolution data on the roughness of the landscape both for estimating water balance components and for distinguishing between landscapes. Models of the scale-dependent roughness are needed to find scales most appropriate for these purposes. Our objectives were to apply fractal scaling to high-resolution profiling laser altimetry data and to determine fractal parameters fro differentiating land cover. Data were collected at the USDA-ARS Jornada Experimental Range in New Mexico over grass-dominated and shrub-dominated sites along four transects at each site. Scale-dependent root-mean-square (RMS) roughness and data power spectrums were computed from 100,000 data points (~2 km) from each transect. A linearity measure and piecewise linear approximation were applied to find intervals of the fractal scaling. The RMS roughness data had two intervals of self-affine fractal scaling on grass transects and four such intervals on shrub transects. Reduction in the number of data points did not lead to a decrease in roughness but caused a smoothing dependency of fractal dimension on scale. Ten- and hundred-meter scales were appropriate for distinguishing between grass and shrub transects on the basis of fractal dimensions. Published by Elsevier Science Inc.

%B Remote Sensing of Environment
%V 61
%P 150-161
%8 1997
%G eng
%U files/bibliography/JRN00238.pdf
%M JRN00238
%L 00763
%) In File (05/07/01)
%R 10.1016/S0034-4257(96)00249-0
%F 1131