Research On The Development Of Field Spatial Information Management System Based On GIS Component

This research was carried out at the Key Laboratory for Modern Precision Agriculture System Integration Research of Ministry of Education, the Research Centre for Precision Agriculture of China Agricultural University, and supported by the National Development Project Committee and Beijing Government Project - Hi-tech Industrialization Demonstration, Beijing Precision Agriculture Demonstration Project (Project No.A00300100584).For site-specific crop management of precision agriculture, it is needed to manipulate mass and various data gathered from different data sources. Since common management information systems are not suitable to deal with these spatial distributed data, it is needed to develop a field level geographic information system (FIS), in order to meet the needs of field data processing and field information management. Driven by the needs for carrying out precision agriculture research, a field-level geographic information system was designed and developed, based on the study of spatial information processing techniques. The main results are listed as the following:1. According to the modern software engineering technology, the system develop models and fashions were analyzed and compared. It was designed using a high-level programming language (VB6) and a geographic information system component (MO2) to develop the system, in accordance with spiral model.2. In order to obtain the digital base map of the field, different mapping techniques were compared. Single point repeat positioning - average and continuously positioning - moving average methods were designed for GPS mapping.3. For geographic coordinates and Cartesian coordinates transformation a model that include 7 parameters and the Guess-Kruger projection were used. The difference of calculation between the above method and Trimble TGO software is less than 1cm.4. In order to keep the digital base map up to date, methods of using remote sensing images as the reference for map refreshment were studied. A 2-D multinomial geometric correction quadratic model was used to correct the geometric distortion of images, and a file contents 6 parameters was used for images coordinates register.5. For lower the soil sample cost, a directed soil sample method was designed. This method could set sample points only at key locations in the field, according to the analysis result of the referenced field information.6. For yield map generating, a local-averaging interpolation method with a random error yield data filter was designed; And for field information distribution map generating, an IDW interpolation method with a smoothing parameter was used.7. Fuzzy integrative evaluation and cluster analysis was used for field management zoning. The results of these two methods were similar.8. A method for calculating the yield goal was developed. The method takes the maximum possible yield of each location that limited by the yield-restricting factor as the yield goal, and generates the yield goal map accordingly.9. For calculating the variable fertilizing dose, a mathematics model was selected. The model takes account of the yield goal, soil fertility, fertilizer available ingredientcontent, and the fertilizer using efficient.In the Beijing Precision Agriculture Demo Farm, the system was used for base map mapping, field boundary map update, soil nutrition map generating, yield map generating, and field basic information management. The result shows that the system is steady and effective to do these jobs, and could be a tool for field data processing and field information management.