绘制尺寸固定的网格化嵌入式地图数据结构研究

Grid Map Database Structure of Fixed Rendering Scope for Embedded System

为了提高导航地图显示数据的读取效率和渲染速度,需要对地图显示的对象进行合理的组织。首先建立了多比例尺二级定幅网格索引结构,基于此索引结构设计了预估缓存加载机制,重点改善了导航定向移动工程下的数据加载性能,从而降低了数据的平均读取时间。在网格内部处理中,根据肉眼分辨特性,提出了显示矢量数据的视觉精简准则,据此在网格内部进行了拼接、简化、合并等预处理精简操作,在保证视觉效果的基础上,减小了用于渲染的数据量,提高了渲染效率。

To improve the efficiency of data query and rendering speed of navigation map display, it is necessary to organize the display objects of map into structures. A dual level grid structure of fixed rendering scope for multi-scale map database was proposed, and based on this structure we designed a forecast loading strategy to improve the efficiency in directional moving navigation, and thus the average data loading time can be reduced. In the grid interior processing, a vision retrench rule was presented based on ocular distinguish characteristic. Using this rule, we retrenched the display objects inside the grids by appending, simplification, and merging, and thus we reduced the data amount in the grids and improved the rendering efficiency with map vision effect still maintained.