基于矢量瓦片的点状要素注记处理技术

Annotation Processing Technique of Point Features Based on Vector Tiles

矢量瓦片体积小,可高度压缩,受网络带宽开销和存储空间的限制较小。地图瓦片化对桌面软件点注记处理带来挑战,不仅是点注记的处理存在重要注记被次要注记压盖、同级注记之间互相压盖、注记与要素压盖等问题,同时瓦片化也带来了注记被瓦片边缘截断显示不完全的问题,这些问题严重影响了地图的可读性和信息传递功能。本文针对以上问题总结了矢量瓦片点注记处理原则,通过设计矢量瓦片的组织结构,确定注记搭配表的JSON组织形式,明确矢量瓦片点注记的绘制流程,根据矢量瓦片特点使用四叉编码进行目标过滤,使用R树作为高效空间索引,并采用基于注记优先级的避障技术解决上述点注记处理带来的问题。

The vector tile is small in size and highly compressible,which is less constrained by the network bandwidth overhead and storage space. Compared with the desktop point annotation processing,Vector tiles not only faced the problems that the important annotations are overlaped by the minor annotations,the same level annotations are overlaped mutally annotations and elements are overlaped each other,but the problem that the annotation is cutting by the edge of the tile is not fully displayed. These problems have seriously affected the readability of the map and the function of information transmission. Aiming at the above problems,this paper summarizes the principles of vector tile point annotation processing,designs the organization structure of vector tiles,determines the JSON organization form of annotation collocation table,clears the drawing process of vector tile point annotation,uses quadtree coding to target filtering according to the characteristics of vector tiles,and uses R-tree as an efficient spatial index,and uses note-based priority obstacle avoidance technology to solve the above-mentioned problems caused by processing points.