Using lacunarity index and wavelet analysis to characterize scale-dependent landscape heterogeneity of Hotan Oasis in China

摘要

Spatial heterogeneity with scale multiplicity inherent is the most fundamental characteristic of all landscapes, thus multi-scale analysis is imperative for understanding the structure, function and dynamics of landscapes. Lacunarity index and wavelet analysis were employed in this study to determine landscape heterogeneity and multi-scale spatial patterns of Hotan Oasis by using RS and GIS techniques. Spatially distributed scale-dependent regularities of land cover types across a range of patch sizes were revealed by changes of lacunarity curves and wavelet variance. The analysis on oasis landscape and zigzag transect showed that lacunarity index exhaustively sampled oasis landscape to quantify its contagion and self-similarity in multiple scales, and Mexican-hat wavelet transformation accurately matched the variance peak and pinpointed the characteristic scale of oasis landscape pattern. Distribution feature and spatial heterogeneity of Hotan Oasis, as well as density of each land cover type, were analyzed in multi-scale and explicitly exhibited. The results prove that lacunarity index and wavelet function are complementary in oasis land use pattern analysis and quite effective to quantify the scale-dependent spatial heterogeneity, finally contribute to the discovery of the relationship between pattern and process of oasis-desert landscape.