Land Evaluation For Tea Garden In Shandong Province Based On GIS: Technology And Methodology

In the past 10 years, GIS had been a prodigious development in application on land evaluation, which is becoming more and more exact and rational. However ,as supporting technologies in land evaluation, GIS still exists problems such as analog accuracy of appraising impact factors' space distribution.This paper emphasizes two aspects, one is space distribution analog technical method of climatic factors based on DEM, the other is land suitability evaluation method combined of GIS and mathematical models. Concrete contents are as follows:1. This paper generalizes achievements and problems in land evaluation, especially in land suitability evaluation technology and methodology. Also it points out key problem in modern research is how to improve analog accuracy of appraising impact factors' space distribution.2. This paper chooses typical district as research areas, which have fine natural conditions and abound experience in tea-introduction. Through analysing characteristic of tea growth bio-geonomy in typical regions, it builds the index system of land suitability evaluation of tea in Shandong province.3. To count restrictive factors' spatial data such as soil, lithology and climate resources, this paper arranges dada and processing, generates special cartographic database and DEM.4. This paper expresses the principle and technical process of solar radiation simulation based on DEM. Also analyzes distribution of study area annual direct radiation and mountain diffusion of solar radiation.5. Under the complex hilly topographical condition, the technical method (weather station temperature data interpolation, altitude correction, then radiation revising processing) is brought out.6. This paper has analyzed relations between north tea freeze and wind field, elaborated wind speed change pattern under complex terrain, produced streamline sectional drawing when air current blows through hillside, and analyzed wind speed difference of different terrain spot under terrain dynamic action.7. Based on classifying single factor appraisal to various senate factors, it applies space analysis of GIS and fuzzy mathematics appraisal models, and evaluates land suitability of tea in typical area.The main innovative spots follow as such:First, land suitability evaluation index system of tea in Shandong province is established. Second, technical method is put forward which is based on the spatial interpolation technique and considering the effect of altitude, slope degree and slope aspect to the air temperature by the method of air temperature lapse rate and the correlation between solar radiation and air temperature.Third, This paper describes the basic model of wind speed chages in complex terrain, analyzes wind speed differnces of different topographic area. This paper describes the center grid point wind speed simulation method according to the relationship between geomorphy position and wind speed based on GIS software, an AML program is designed to simulate the distribution of wind speed.Fourth, this paper uses appraisal method associating GIS and mathematical model, which enhance technical method of land evaluation.