地理信息系统和遥感技术支持下的山地环境梯度分析方法研究*

文章提出了一种地理信息系统和遥感技术支持下的环境梯度分析方法。应用该方法可将研究区域的TM遥感影像经遥感图像处理和分类得到该地区的植被类型分布图,充分应用地理信息系统强大的空间信息管理和分析功能,将各环境因子分布图分别与植被类型分布图进行叠加分析得到各种植被类型与各环境因子关系的向量表达式,进而建立符合环境梯度分布的植被空间分布模型。在此基础上,综合各环境因子分布图与植被类型分布图进行叠加分析和植被群落空间分布制图。该方法曾应用于贺兰山环境梯度分析并得到较满意的结果。

THE METHOD OF MOUNTAIN ENVIRONMENT GRADIENTANALYSIS BASED ON GEOGRAPHIC INFORMATIONSYSTEM AND REMOTE SENSING TECHNOLOGY

The aim of environment gradient analysis is to explain the inter spatial relationships of each kind of environment factors. Although so many methods have been used for the analysis , the shortages of the traditional research , heavy work amount and operation miscellaneous , have not been overcome. On the base of the geographic information system (GIS ) and remote sensing technology , a new method and flow-line of environment gradient analysis are set up in this pa- per . The advantage of the new method lies in simple operation and time-saving. With the remote sensing image processing software , the TM image of the research area was processed , classified , and the vegetation distribution map was produced quickly. The GIS also provides powerful spatial analysis ability such as overlay for multiple thematic maps integration analysis. In this paper , four environment factors , elevation , precipitation , soil and temperature , were selected and their thematic maps were overlaid with vegetation distribution map to analyze the relationships between vegetation distribution and them. In order to benefit statistics , the value of each environment factor was transformed into several gradients under certain condition respectively. On the unit of gradient of each environment factor , the distribution amount of each kind of vegetation is counted up by overlaying the vegetation distribution map and the distribu- tion maps of other physical environment factors. The results show that the distribution of each kind of vegetation related to the environment factors concerned is approximately normal and the peak value of each normal is the best representative of the kind of vegetation. Thus , the vector expression with the normal distribution peak value of each factor can be used to describe the re- lationship between the environment factors and each kind of vegetation. And , the model of the differentiation of vegetation. community spatial distribution conformed to the environment gradi- ent was built. Four thematic maps of selected environment factors were overlaid together to re- classify the vegetation distribution map depending on the above model and minimum distance classification method. The method was tested in the case study of Helan Mountain , and the re- sults are satisfactory.