Based on the analysis of Vega the callback technology of OpenGL is used and the Chinese characters two-dimension display and three-dimension display in Vega are realized .

在对Vega研究的基础上，采用OpenGL回调技术，实现了Vega中汉字的 二维及三维 显示。

Currently most applications use two-dimension GIS to design but reality is a real three-demension space so can not display reality .

目前，在城市规划方面主要采用 二维GIS来进行平面设计和应用，但是现实世界是真实的三维空间，故不能较好的 显示真实世界。

However most of these systems were using two-dimension ( 2D ) display form for pipe-network observation and management which can not show the depth information .

但这些系统大多使用 二维 显示的方式来实现对管网的管理，无法实现对管网纵深的显示。