芦苇面积，苇下水位变动和邻近水域大小等是影响鹤类生境选择的重要因子，通过建立向海地区的数字高程模型 (DEM)，将其与从遥感影像上获取的向海湿地景观信息在ARC/INFO模块下进行空间叠加分析，建立了水位与芦苇分布的动态关系。通过模拟得出：当湿地水位达到165 m时，鹤类可选择的生境面积最大，为981.2hm²。此外，本文还模拟了不同水位以上芦苇面积的等级分布规律。该模拟结果对于向海自然保护区鹤类生境的优化管理及主要供水源向海水库的科学管理具有重要的参考价值。

The probability of crane living in reedy wetlands can reach 100%, at the same time, the area of reed, the water level and adjacent water area are main factors which control the crane's habitat selection. We all know that all these factors are spatially heterogenous. For the sake of Xianghai wetland safety and of protecting the Xianghai wetland habitat of crane, this paper mainly has found a method to solve these problems. The wetland information is extracted from the TM images, which reflect the whole wetland landscape and are very important for both quantitative analysis of remote sensing observation of the earth system and positioning analysis in GIS database that is automatically extracted from DEM. The DEM for Xianghai characteristics of topography is created. On the basis of the GRID SUBMODULE, applying the GIS spatial overlay analysis, the relationship between the water level and the reed area below the water level and the rating distribution maps of reed area above water level is established. When the water level reaches the altitude of 16 m, the reed area, 981.2 hm², is the maximum, i.e., the water level of 165 m is the optimal.