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In china, with the development of GPS, GIS, RS, 3S technology is gradually used in the agriculture in recent years. This paper introduced the concepts of GPS, GIS, RS. Considering the fact of the Chinese agriculture, we developed the farmland information support system based on the integration of GPS, GIS, RS. With the application of this system in some counties of Yunnan province, the work mode of the department of the agriculture has started to be changed.

Based on SRTM DEM data, Arc Hydro Tools of ArcGIS is firstly employed with Red River as an example in this paper. On the basis of D8 algorithm, the authors then confirm flow direction of raster units according to the steepest gradient as well as starting-point and end-point of river section by means of threshold catchments area. Next, searching for upstream water-supply district of each river section from sub-watershed exit, the boundaries of whole watershed and each sub-watershed are obtained, which will finish characteristics extracting and generate digital Red River watershed. Eventually, experiment result of watershed is analyzed.

With the development of the project of Formula Fertilization by Soil Testing in china,in order to investigate the soil condition,fertility level,nutrients status,soil degeneration status and the farmland integrated productivity of china,the government decided to start up the project of the Evaluation of the farmland productivity with the field investigation data and the analysis assay data, which were got in the project of Formula Fertilization by Soil Testing. Based on the spatial analysis function of the geographic information system(GIS), such as overlay analysis and spatial interpolation,using soil image,Present land use map and administrative map of the poroject area?this research decided evaluation unit and connected the field investigation data and the analysis assay data. Considering the actual conditions of the poroject area, the experts selected Sixteen affected factors from four aspects as land management?land growing situation?profile situation and soil nutrient content?and the evaluation system of farmland fertility of was built up?Aimed at the affected factors,It adopts the Delphi method to identify the membership function of severa1 affected factors and introduces Analytica1 Hierarch process (AHP) to calculate the weight of evaluating factors.On the basis of these datas,this research used the Additive Model to calculate the Integrated Fertility Index(IFI) and also analyses its space distribution?Because The results are in 1ine with the local situation of the city,This result can be applied to agricultural production.

Parallel editing of spatial data is one of the concern focuses in GIS research. The paper firstly discusses current status of research and analyzes mechanism and implement method of ArcSDE version management. With ArcObjects component as exploitation platform and Visual Basic as tools, a version management component is designed and developed and integrated into application software which implements multi-users parallel editing and version management of spatial data.