利用IKONOS卫星数据和分形方法研究南麂岛土地覆盖状况

研究南麂岛的土地覆盖类型及其空间分布和结构特征。利用具有1米空间分辨率的IKONOS卫星遥感数据，提取南麂岛的植被覆盖和土地利用信息，获得草地、灌木林地、庄稼地和居民地等主要土地覆盖类型及其分布图。然后利用分形几何方法建立南麂岛土地覆盖类型特性分析模型，从斑块的面积效应、覆盖类型的分形分析、单个斑块的分形分析和覆盖类型分形特征差异显著性等方面进行分析讨论。研究结果表明，南麂岛的草地和灌木林地的分形维数较大，而庄稼地和居民地的分形维数较小，说明草地和灌木林地的斑块的结构特征和边界比庄稼地和居民地更为复杂。进一步研究表明，斑块的分形特性与其受人类活动的干扰程度密切相关。

Study of land cover on Nanji Island using IKONOS images and fractal approach

The purpose of this paper is to study the distribution and fragmentation of land cover types of the Nanji Island, China using IKONOS images and fractal approach. IKONOS images are used to survey the land uses and land covers. Fractal theory is employed to analyze the edge effects caused by habitat fragmentation and land type structures.;To derive the land type information from IKONOS images, the threshold method, vegetation index method, false color synthesis method, data fusion method and man-machine interactive method are employed. The threshold method is used to derive the shoreline information from near infrared images while the normalized difference vegetation index (NDVI) is employed to extract the vegetation information. The false color synthesis method and data fusion method are used to process the data in order to obtain false color images. The man-machine interactive method is used to derive information about the village, farmland, water body and sands from the false color images based on the texture and tone of the images. ;The characteristics of the land cover patches are described quantitatively by the fractal dimensions which are calculated by the perimeter-area method and measure-perimeter-area method. Based on the fractal dimensions, the effects of patch area and fractal characteristics of land covers are analyzed.;The results obtained from the present investigation are as follows: (1) The main land cover types in the Nanji Island are meadow, shrubbery, farmland, village, water body and sands. Meadow and shrubbery are the dominant types, and cover 89.6% area of the island. (2) The patch number, fractal dimension of the patch and patch perimeter are related to patch areas. The patch number decreases with increase of the patch area whereas the fractal dimension increases with increases of the patch area. The patch perimeter has the linear relation with the patch area. (3) The fractal dimensions of the meadow, shrubbery, farmland and village calculated by the perimeter-area method are 1.3433, 1.3728, 1.2563 and 1.2156 respectively. On the other hand, the fractal dimensions of the meadow, shrubbery, farmland, village, water body and sands computed by the measure-perimeter-area method are 1.096, 1.102, 1.05, 1.062, 1.002 and 1.047 respectively. Thus, it is concluded that the meadow and shrubbery have higher dimensions compared with those of the farmland and village. It is indicated that patch structures of the meadow and shrubbery are more complex than those of the farmland and village. Studies also show that the fractal characteristics of land covers are related to the human activities. (4) The test of significance of fractal characteristics shows that the differences between the meadow and shrubbery and the farmland and village are significant whereas the difference between the meadow and shrubbery and the difference between farmland and village are insignificant.