A Research On The Application Of Graphic Query System For Data From Automatic Weather Stations

The development of an entire graphic query system for data from Automatic Weather Stations (AWS) is associated with a lot of work, such as the quality control of meteorological data, the applications of GIS, etc. In this paper, several key issues have been disscued during the design of the abovementioned system, and also the sulotions of the issues have been put forward.1. Beginning with the presentation of the conceptual spatiail variogram theories, 7 spatial interpolations have been introduced.After a large amount of data statistics and comparisions,The Time CoKriging was selected as the best model of spatial quality control. And according to the initial documents retrieving, we are the first to apply this model in the fields of quality control for meteorological data. Finally, the quality control software for data from ASW was designed and implemented.2. Surfer Automation supports Distribution Component Object Mode(lDCOM),by activating which, Surfer ActiveX will be called to draw contour on web pages. A rule of naming the contour graphical files and the algorithm of building the abovementioned files are discussed, with which, the repeatedly search of database and generation of images are avoided so that the speed of image display increases, and simultaneously, the write violation, which is probably caused by mass parallel access, is avoided. Eventually, the problem of calling Surfer ActiveX is resolved. The load test indicates that the speed of drawing contour on web pages by using the algorithm is increased by twice as much.3. By studying the earth coordinate system and deeply analyzing the algorithm of Google Map, the recent URL format of the Google Map tiles is discovered and the verified program is coded to download the tile files of the specified area. With these files, a tiling map server can be made in the future so as to lower the risk of depending on Google Maps totally. At the same time, the reason causing the offset of Google Map China is found, and a simple and pragmatic method of correcting the offset of the coordinate system is put forward. The actual measurement shows that the average distance between coordinate system corrected and WGS-84 is less than 30 meters.4. In combination with the techniques of drawing contour with surfer, the contour and images of radar can be overlaid to Google Map. And also, the driving route between any two automatic weather stations is calculated in order to make the maintenance more easily. 5. The Graphic Query System of data from Hainan Automatic Weather Stations has been designed and developed. The load test result shows that the performance of the system can meet the requirement of the current business.