基于格网GIS的关中地区生态安全研究

Ecological Security of Guanzhong Region Based on Gridding GIS

选择城市化进程不断加快的陕西关中地区为研究区，依据“压力-状态-响应”模型建立了格网化区域生态安全评价体系，在格网GIS技术的支持下，对评价体系中各指标进行1km×1km尺度下的网格化表达，运用基于栅格数据的空间叠加方法实现生态安全模型评价，得到格网化关中地区1990年、2000年和2007年生态安全指数空间数据，在此基础上结合关中地区实际，定性与定量相结合地确定了生态安全评价等级划分阈值。对计算结果进行分析，总结出1990—2007年间关中地区生态安全特点有三，一是总体呈现出生态安全状况逐渐转好态势，但仍处于不安全状态；二是区域内生态安全变化存在明显差异；三是不同年份生态安全影响因素有所差别。研究结果表明，格网GIS用于研究生态安全能更好地反映其内部差异，优于传统研究方法。

For recent years, there were still some deficiencies in the ecological security research. For example, the spatial scales were not quite reasonably selected and the thresholds of ecological security ranks were determined with the lack of practical significance. And all these maybe decrease the credibility of research results. Therefore, for the current lacks of ecological security research, choosing the Guanzhong region with accelerating the urbanization process as study area which is located in Shaanxi Province, this paper built up the regional ecological security evaluation system on the basis of ＂ pressure-status-response＂ model and gridding methods. In support of the gridding GIS technology, this paper gave each index in the evaluation system the spatial expression of 1 km x 1 km grid scale. Subsequently, using the spatial overlaying technology based on grid data, this paper achieved the modeling evaluation of ecological security and acquired the gridding spatial data of every ecological security indexes for Guanzhong region in the year of 1990, 2000 and 2007. With the software of GIS, the paper carried out the spatial overlay analysis based on raster data and acquired the gridding data of ecological security of Guanzhong region. Combined with the reality of Guanzhong region, and referred to the current situation and circumstances of national forest parks and nature reserves, the paper tried to determine the threshold used to etassify the ranks of ecological security by means of qualitative and quantitative methods. The results show that there are three features of ecological security of Guanzhong region. First , the ecological security of Guanzhong region is overall becoming better and better, but it is still unsafe; Second, the ecological security changes have the significant differences within the region. Third, there are different factors of affecting ecological security in different years.