The System Of Prime Farmland Protection Planning Based On Integrating GIS With Decision-making Models

Prime farmland protection planning is an important content of land use general planning, which is the process of selecting determinate quantity of cultivated land into prime farmland from the cultivated land planned by land use general planning. Scientific and reasonable prime farmland protection planning is very important for protecting cultivated land, stabilizing agricultural production and promoting sustainable development of social economy. However, now the factual planning is always lack of scientific decision-making and objectivity, pursuing the quantity of prime farmland one-sidedly while neglecting the quality, which leads to prime farmland protection in form. In addition, in technical method of planning, although application of computer substitutes for conventional manual method step by step, the decision-making of planning is still manual work. At present, some prime farmland protection planning information systems have been developed based on GIS, but most of them are restricted to decision process of quantity such as demand forecast of prime farmland, not involving in decision process of spatial distribution, which can not realize the automatization of prime farmland protection planning. So aiming at the problems of present prime farmland protection planning, the dissertation sets up a decision support system for prime farmland protection planning by forming relevant aid decision-making models and integrating with GIS to realize decision visualization, which can provide technique support for planning the prime farmland protected area scientificly, reasonably and efficiently.Firstly, according to the content and procedure of prime farmland protection planning, the dissertation puts forward that the key technology of prime farmland protection planning includes quantity determination and spatial distribution of prime farmland. Then it discusses the principle of solving the two problems scientifically. The quantity can be determined by demand forecast, the quantity sent down by the higher authority and the cultivated land area stated in land use general planning. And the determined quantity of prime farmland can be breakdown to the administrative regions at the next lower level based on the condition of population, cultivated land, reserved resource and occupation of cultivated land. Spatial distribution of prime farmland is a complicated decision-making problem, which involves three logical correlated parts: ranking cultivated land synthetically, selecting cultivated land into prime farmland and partitioning polygon in determined area. Ranking is the basic and key part in the spatial distribution of prime farmland because it directly influences on the results of selecting.Secondly, based on the principle of the key technology, corresponding decision-making models have been set up. In ranking the indicator system of affecting cultivated land being selected into prime farmland has been built firstly, which is composed of 18 indicators involved in quality, location, policy attribute and administrative intervention of cultivated land. Then based on the character of ranking, the idea of combination decision has been brought forward, ranking cultivated land synthetically with three ranking models including a model by similarity to ideal point, fuzzy optimization model and attribute hierarchy model. In three models the weights are based on hierarchy analysis and entropy weights,considering not only subjective partiality but also the intrinsic information of decision objects, which make the ranking results more scientific, reasonable and credible. Selecting cultivated land into prime farmland is the process of determining every cultivated land plot wether being selected into prime farmland or not according to the ranking results and the quantity of prime farmland. A 0-1 integer programming model can solve this problem. Partitioning polygon in determined area is a graphic processing for ensuring the exace location of prime farmland. It can be settled by the method of approach. Polygon partition c...