Study On The Agricultural Land Classification Based On GIS And Fuzzy Comprehensive Evaluation

Agricultural Land Classification has been getting by the modifying method in the Regulations on Farmland Gradation and Classification issued by the Ministry of Land and Resources, P.R.C at the present time. The method makes the farmland grades through the exponent of farmland grade, which is got through modifying by the nature quality of land, the utilized level of land and the economic level of land based on temperature productivity potentiality (climate productivity potentiality).Agricultural Land Classification is very complex process, is made by synthesizing the nature quality of land, the utilized level of land and the economic level of land, but the result is checked up by traditional experience in the Regulations on Farmland Gradation and Classification. This is contravention with the accurate process of Agricultural Land Classification. The question that we must find out the method to check up the result of agricultural land classification is solved quickly currently.The paper established the technical route and flow of the fuzzy comprehensive evaluation through analyzing the elements of the modifying method and the fuzzy comprehensive evaluation finally. Based on the above, the paper used ArcGIS and Visual FoxPro as the flat of data processing, combined with the agricultural land classification of Jilin province and established the models of the modifying method, the fuzzy comprehensive evaluation and carried out the grades of Daan city taking the region of Daan city as an example.The paper has reach conclusions as following through analyzing the result of farmland grades :1. Agricultural land classification is the appraisal of the quality of farmland synthetically. This appraisal is represented in the nature quality, the society and the economy of land. Agricultural land classification is fuzzy classify, so it could combine determine the nature with the ration effectively and check up the result veracity of agricultural land classification preferably.2.According to Procedures and Rules for Farmland Grading issued by the Ministry of Land and Resources, P.R.C, after researching the basic methods and technological routes technologies, data of farmland grading, research ethods, such as GIS analysis and investigation, qualitative analyses, general means and computer technology are used and quantitative in the selected example region of Gaoyao of Guangdong Province to carry out farmland grading research.3.According to the result of the agricultural land classification, 85% of grading cells of farmland are identical, the fuzzy comprehensive evaluation has acquired effect in agricultural land classification and the result, which has been got by the fuzzy comprehensive evaluation, could validate the result got by modifying method.4.In the factors that compose nature, society, economy of farmland, some could be calculated accurately, but the data could not be collected and some factors could not be calculated as involved the parcel. At the same time, the error of calculating will be passed point-blank in the modifying method. The fuzzy comprehensive evaluation could reduce the error through evaluating the quality of farmland by multilevel fuzzy comprehensive evaluation.5.The fuzzy comprehensive evaluation has offset the disadvantages that data and people in the modifying method could influence the result. Carrying out the fuzzy comprehensive evaluation to calculate the data of factors would swell the contrast of factors and reliability of result. The fuzzy comprehensive evaluation could check up the result which is got by modifying method and it provides the method which is used to check up the result in reason.