基于GIS的农用地连片性分析及其在基本农田保护规划中的应用

基本农田保护区的划定是一个科学的、系统的问题,以往主要考虑数量、用途、质量和位置等因素.该文提出农用地连片性的概念,即同一质量范围(同一等级,或某一等级以上,或某等级区间内)的农用地地块相连程度.力图以之判断优质集中农用地的空间分布,并提议将此概念纳入基本农田保护区的确定程序中.国内外有关连片性的研究大多集中在景观生态学领域,国内也有文章涉及到耕地连片程度的问题,但在数学方法和理论上还有待进一步探讨.该文结合农用地分等成果,设计了3种农用地连片性的计算方法:空间相连性计算法、模糊纹理定量方法、基本农田保护指数方法,并以贵州玉屏侗族自治县为例,采用空间相连性计算法,在地理信息系统(GIS)的支持下,计算了不同约束条件下基本农田划定的空间范围,从而验证了该方法的可行性.实例研究表明,此方法的应用具有3个优点:1)连片的面积不再有最小和最大极限:2)连片的土地不限于零距离的相连:3)连片土地的质量等别可以自定义调整.

GIS based connectivity analysis and its applicationin prime farmland protection planning

Prime farmland protection planning is both a scientific and a systemic work. Current protection planning mainly considers quantity, purpose, quality and location of the land, rarely considers the connectivity of farmlands. Large connected quality farmlands clearly have higher value for protection than small isolated ones. This paper gives a concept of connectivity of farmland, which means the connective degree of farmland with similar quality (same rank of quality, or all above a certain level of quality, or a rank span). This paper tries to figure out the distribution of better and connective farmland with connectivity concept and suggests putting this concept into the principles of prime farmland protection planning. The research of connectivity in home and abroad focuses on landscape ecology. It is a lack of research about mathematical methods from theoretical view angle, although scholars did work on the connective degree of farmland. Based on the result of farmland ranking, this paper provides three ways for measuring farmland connectivity under GIS environment: connectivity analysis, fuzzy texture analysis and quality-weighted fuzzy index. Taking Yuping County in Guizhou Province as a research field, the authors apply the way of connectivity analysis to computation and mapping the areas of prime farmland by ArcGIS, which can meet varied limits and demands. The result proves the possibility of the method. This case study shows that the method has three applied advantages: 1) Elimination of the need for arbitrarily specifying the minimum and maximum patch sizes for protection; 2) Linkage of patches which are not touching but still close in space; 3) Flexibility of user-defined quality levels.