基于GIS和DEM的北京西部山区经济林果适宜性评价

山区地形多变,造成了自然资源立体差异显著,如何定量表示各种农业资源在山区的具体分布状况和建立土地评价模型,是山区资源开发利用和农业结构调整所需要的。该文利用数字高程模型,建立山区日照的地形遮蔽分析模型,在此基础上可进行任一时间、位置的日照时数,辐射等气候因子的地形校正,同时利用统计模型和GISSpline插值技术对温度、降水进行简单的地形校正,与土壤质地图、土壤母质图、土壤厚度图以及土壤pH图,坡度、坡向和海拔高度一起建立了评价因素数据库,从而为土地评价、生态环境分析等领域提供基本参数。以果树适宜性评价为例,利用模糊隶属度函数表征和量化了果树生长生态要求和生态评价因素间的关系,有利于评价专家知识和关系的简化计算。采用简单的等权求和完成多评价因素综合,回避权值确定的主观性等复杂问题。最后以7种有发展潜力的果树利用该评价模型,以门头沟为例,进行了实证研究。除樱桃外,其余6种果树高度适宜的面积都在上千或万公顷以上,因此该区有极大的经济果林发展潜力。该区域现在的果树面积与20世纪90年代初期相比,扩大了3倍多。该评价结果帮助当地政府确立了林果特色经济发展区的农业结构调整政策。通过DEM校正技术,可以较为准确地建立山区生态因子数据库,通过模糊隶属度函数可完成定性和定量的土地评价知识的综合表示,通过等权求和方法,在GIS技术的支持下可以准确快速完成评价过程,从而为山区综合可持续发展服务

Suitability Evaluation of Fruit Trees in Beijing Western Mountain Areas Based on DEM and GIS

Under leading of the WTO market regulations, the reasonable exploration and sustainability utilization of Beijing mountainous resources were very vital to the mountain areas and the whole development of Beijing. Because of the varied topography of mountain areas, it was important to quantify and imitate the spatial heterogeneity of ecological factors in Beijing mountain areas. In this paper, 1∶50 000 scale DEM (digital elevation model) was built. Then the evaluation factors of slope, aspect etc were derived from DEM through the surface analysis function of Arcview software. Through the meteorological point data of this area, the sunshine duration, average yearly temperature and precipitation were modeled through DEM for the whole region. The results supplied the basic quantified ecological factors for fruit trees suitability evaluation, habitat simulation etc. On the other hand, with the help of the digital soil types map, soil texture map, soil depth map, soil pH map, geological type map of this area, the fuzzy sum method was used to evaluate the suitability ratings of fruit trees in this area through GIS. Seven fruit tree varieties with large market potential in Mentougou District were evaluated by this model. The acreage of these fruit trees except cherry was more than one thousand or even ten thousand hectares. On the basis of the actual land-use data from remote sensing classification, compare the results with the current distribution of fruit trees, the shortcomings of the current distribution of fruit trees and potential of future development were analyzed, and then 参考文献 to the readjustment of current agricultural structure was supplied.