以科学发展观为依据,采用三维魔方图分类法对广州市进行主体功能区划,划分为禁止开发区、限制开发区、重点开发区、优化开发区和土地储备区。在此基础上以30m×30m的栅格作为最小的评价单元,从土地资源数量安全、质量安全、经济安全和生态安全四方面构建土地资源安全评价指标体系,并利用改进的支持向量机模型(SVM)进行评价与分类。结果表明:①广州市主体功能区划具有明显的方向性,其中禁止开发区占总面积的37.21%,限制开发区占24.90%,重点开发区占19.60%,优化开发区占13.31%,土地储备区占4.98%;②土地资源安全分值介于16~82之间,不同行政区土地资源安全状况具有明显差异,土地安全分较高的主要有南沙区和花都区,而荔湾区土地安全分最低;③广州市土地资源安全形势不容乐观,危险区和较不安全区占评价面积的比例达32.35%,主要分布在增城市和从化市的偏远山区以及市中心的荔湾区及越秀区,单位建设用地GDP、人均居住面积和归一化植被指数是其主要警源因素。
Based on the theory of scientific concept of development, the space of Guangzhou is divided into the optimized development zone, the emphasized development zone, the limited development zone, the forbidden development zone, and the land reserved zone. After that, this paper constructs the security evaluation indexes from four aspects consisting of land quantity security, quality security, economic security and ecological security. The values of land security in Guangzhou were calculated through model of support vector machines by a grid of 30 m ×30 m as the smallest appraisal units. The main conclusions are drawn as follows: (1) The forbidden development zone is 2766.00 km2, accounting for 37.21% of the city's total area. The land permitted to develop is 1851.07 km2, or 24.90% of the city's total; the emphasized development zone 1457.09 km2, or 19.60%; the optimized development zone is 992.46 km2, or 13.35%; and reserved zone area is 370.61 km2, or 4.99%. (2) Five types of safety grades are identified, with the value ranging from 16 to 86, but different districts are in different safe ranks. The best safe condition is Nansha district and the worst is Liwan district. (3) The result shows that the situation of land security in Guangzhou can not be optimistic. The percentages of dangerous and unsafe areas add up to 32.35%, which are mainly concentrated in remote mountainous suburbs and center of the city. GDP of the per unit construction area, the per capita living space and NDVI are the main factors affecting land resources security in Guangzhou.