Researches On Geological Data Integration And Publishing Based On Web Technology

For the sake of serving the exploration and utilization of mineral resources better, now it's of vital importance to make geological data serve the society, and nowadays there is an apparent trend to share geological data over internet.Currently, the WebGIS technology is the major method used in this area. However, this traditional WebGIS technology has obvious weaknesses of slow publishing speed, high network traffic and poor interaction ability. In this case, it can't meet the needs and demand of online service of massive geological data. This problem has become the bottle neck of its development. Meanwhile, the geological data has its own particular characteristics such as being multi-sourced, heterogeneous and distributed. Therefore, it is urgent to solve out this problem and get the data shared and published sufficiently and effectively. Focusing on this problem, this thesis first gave a thorough analysis of the weaknesses of the WebGIS technology, then researched the REST framework and AJAX technology, and finally provided a new map-publishing technology with a combination of pre-generated raster map tiles and pre-rendered vector basemap in which the integration and publishing service for multi-sources of geological data has been implemented. The main contribution of this thesis is summarized as below.The first point is about the publishing technology of geological raster data based on pre-generated map tiles. This thesis provided the publishing idea of pre-generated map tiles and developed the rules of generating map tiles and storage structure of map tiles, and finally made the retrievement of massive map tiles quicker. It also studied the flow of map tiles request and integration and related algorithm and made the map browser go faster. Meanwhile, it delivered a new designing of map window cache, browser cache and server-side cache to improve system performance by shortening access path and decreasing access times.The second point is about the publishing technology of geological vector data based on pre-rendered vector basemap. It put forward the publishing idea of pre-rendered vector basemap and made a combined technology of pre-rendered basemap and thematic vector data come true. Pre-rendered basemap publishing affords users high quality image and thematic vector data publishing affords users dynamic data query. With the combination of the two technologies'advantages, the quality of map publishing and the ability of interactive query have been improved.The third point is about geological data integration and publishing technology. On the basis of raster data pre-generated publishing technology and vector data pre-rendered publishing technology, it put forward multi-sources geological data integration and publishing technology based on OGC webservices and implemented multi-sources geological data's dynamically loading, multi-layers stacking, transparence controlling, map browsing and data querying, and other publishing services and finally provided assistant tools for geological data online integration interpretation.Based on the above technologies and methods, the design and development of a prototype system has been carried out independently. After testing the integrated publishing of 1: 2,500,000 scale geology map, gravity map and aeromagnetic map, it has been validated that this system can apparently improve massive geological data publishing speed, make map browser go smoothly. The system also has flexibility on data query and interaction so that it has completely met the needs and demand of current geological data online serving.