Quantifying change in patterned semi-arid vegetation by Fourier analysis of digitized aerial photographs
Quantifying change in patterned semi-arid vegetation by Fourier analysis of digitized aerial photographs
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DOI：
10.1080/01431160110107699
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发表时间：
2002-09-01
影响因子：
3.4
通讯作者：
Couteron, P
中科院分区：
文献类型：
--
作者：
Couteron, P
利用1955年和1985年的全色航空照片（比例尺：1:50 000）量化了20世纪80年代初连续干旱年造成的半干旱型植被的变化。研究地点位于布基纳法索（西非）的西北部，具有热带稀树草原地貌的平原和被虎灌木覆盖的缓坡。数字化数据（像素大小为3.15 m）覆盖了9 km × 1.5 km的带样带，该带样带被划分为315 m(2)平方样方。四个参考样方被数字化，像素为0.83 m，与1994年的高分辨率前景进行比较。图案量化依赖于傅立叶变换的光谱分析，它产生了主要波长（径向光谱）和主要方向（角光谱）。平原区植被表现出重要的变化，这些变化与草本覆盖（及其相关的散在树木）的崩塌和部分干旱后恢复有关。这种变化被量化为小空间波长的相对下降(
Panchromatic aerial photographs from 1955 and 1985 (scale: 1: 50 000) were used to quantify changes in semi-arid patterned vegetation caused by a succession of dry years in the early 1980s. The study site is located in the northwest part of Burkina Faso ( West Africa), and features a plain with a savanna physiognomy and gentle slopes covered by tiger bush. Digitized data (pixel size of 3.15 m) covered a belt transect of 9 km by 1.5 km that has been divided into 315 m(2) square quadrats. Four reference quadrats were digitized with a pixel of 0.83 m, for comparison with high-resolution outlooks from 1994. Pattern quantification relied on spectral analysis by Fourier transform, that yielded dominant wavelengths (radial spectrum) and main orientations (angular spectrum). The vegetation in the plain displayed important changes that were related to the collapse of the herbaceous cover (and associated scattered trees), and its partial post-drought recovery. Such changes were quantified as a relative decline of small spatial wavelengths (