CAD Polyline线的抽稀与圆滑

在GIS基础数据的采集过程中,数据质量的控制非常重要。介绍了对自动生成的等高线进行圆滑和抽稀处理的一种方法。     

Chain-based polyline tessellation algorithm for cartographic rendering

ABSTRACT

Although the extrusion of 1D polylines into a 2D polygon and the tessellation of the polygon into primitives has been performed in the field of computer graphics, the efficient, robust, and high-quality tessellation of thick polylines that supports various cartographic styles for polyline rendering remains a practical challenge. We examined and compared existing vertex-, segment-, and polygon-based algorithms, and present a chain-based tessellation algorithm for cartographic rendering: points in the polyline are classified into abrupt and smooth points according to their point spacing, angle and thickness. The polylines are then divided into abrupt and smooth chains by clustering points that are adjacent and of the same type. An optimal algorithm is also presented to continuously tessellate the smooth chains into minimum geometric primitives and efficiently tessellate the abrupt chains into geometric primitives. We implemented the proposed algorithm and present the results of robustness, efficiency, quality, and cartographic styling tests conducted on real-world polylines. The results indicate that this approach has substantial advantages when considering all four requirements (robustness, efficiency, quality, and the support for various cartographic styles).     

基于MapInfo平台的线对象分割算法

ＭａｐＩｎｆｏ 是目前国内较流行的ＧＩＳ 应用软件开发平台, 有着较高的性能价格比。但其某些功能往往不能满足ＧＩＳ 应用软件的开发要求。文中针对ＭａｐＩｎｆｏ 分割功能的不足,给出了线对象（ｐｏｌｙｌｉｎｅ） 的分割算法及其实现。     

提高地震数据绘图效率方法研究

这里介绍了一种提高地震波形绘制效率的方法。通过对读取地震数据、处理地震数据、显示地震数据这三个过程方法的改进,减少了数据处理和波形绘制的时间,提高了绘制地震波形的效率。