Research And Application Of WebGIS Based On Native XML Database And GML

Nowadays,many manufacturers, both at home and abroad,are exploiting WebGIS systems based on their own data format and spatial data management, which make it very difficult to share and interact the GIS data between each system.This is the bottleneck of the WebGIS application as well as massive data transmission. Luckily, the appearance of GML and native XML database can solve the problem. GML is a kind of novel,succinct and unified encoding standard for spatial infomation in Internet environment, while native XML database is a database designed specifically to store and process your XML documents. Hence it’s of great importance to study the combination of GML and native XML database during the WebGIS research in order to solve the bottleneck of sharing and interacting the GIS data.Firstly,this paper analyzes the current characteristics and development of WebGIS as well as the bottleneck of data sharing and interacting;deliberates the necessity and superiority of combining GML data-sharing standards with native XML database to solve the problem;puts forward the architecture building of WebGIS based on native XML database and GML; illustrates that it is possible to build the new WebGIS with the combination of GML data-sharing standards and native XML database, after analyzing the comparison with traditional WebGIS architecture.Secondly, this paper designs and makes modeling on GML Spatial data to fulfill the demand of census area statistics application requirements. After the analysis of comparison test on geographic data space storage management between native XML database and traditional spatial relational database, it’s clear that native XML databases is more superiority on average query performance than traditional spatial relational database.Thirdly,this paper starts with application features and data of the GML,for the shortage of great GML plain text data volume of storage and transmission.First,it does lossy compression on coordinate precision of feature points.Second,it does sampling compression using the sampling algorithm of feature points.Third,it does lossless compression on tranmission data, on condition that certain scale error is allowed. It decreases the data volumn of GML during the storage and transmission in the three ways mentioned above,so that the whole system is optimized,which are all proved to be very practical in optimizing GML data by experiments.Lastly,this paper designes and achieves a certain WebGIS statistics application prototype system in one census area,and introduces some key techniques,in combination with OpenLayer framework technology and research results,It’s a new research field to combine native XML database and GML towords WebGIS application.Further more,the study and development of the field will have a far-reaching impact on the process of WebGIS.