基于改进Web墨卡托投影的瓦片地图服务设计与实现

为解决网络地理信息应用二、三维一体化显示需要,通常做法是处理并存储两套不同投影的地图瓦片数据,一套采用Web墨卡托投影,面向二维地图应用;一套采用经纬度坐标,面向三维地图应用。这在一定程度上降低数据处理效率、浪费存储资源。文中提出一种改进Web墨卡托地图投影方法,并设计一种面向影像地图和DEM数据的瓦片化方法。方法生成的影像地图瓦片数据既能同时面向二维地图和三维可视化场景使用,又有效解决Web墨卡托投影不支持高纬度地区栅格地图表达的缺陷。将新型的地图投影和数据模型通过瓦片地图服务系统进行验证,证明这种新改进的投影和影像,以及DEM瓦片化方法具备较高的实用性。

Design and implementation of tiled map services based on improved Web Mercator map projection

In order to meet the integrated visualization requirements of two and three-dimension within network geographic information application ,the usual practice is to process and store two sets of map tile data with different projection .One is Web Mercator projection for two-dimensional map application ,and the other is Lat-Lon projection for 3D map application .This approach reduces the efficiency of data processing and storage resources waste dramatically .This paper proposes an improved Web Mercator map projection .And a tiling method of image map and DEM data is designed according to this new projection . The generated image map pyramid by this method can be used in 2D map and 3D visualization scene .It solves the problem that Web Mercator projection does not support map expression in high latitude area effectively .T his model is validated through a tile map service system .T he results prove the new improved projection ,image ,DEM tiling method is adaptable for the practice .