在分析了传统GIS不足的基础上提出了以大型GIS与数字地球的空间数学基础理论为依据，运用矢、栅结合技术，以数字栅格地图(DRG)作为系统参考背景，用户关心的专业实体适时标注为系统建设技术路线。并以此技术路线开发了基于GIS技术的咸宁市防汛信息系统。该系统为咸宁市防汛工作的科学化管理和决策提供先进的技术手段，取得了令用户满意的应用效果，事实表明本文使用的理论基础和技术路线具有良好的实施前景。

The paper presents a new theory of space mathematicalbase of large－scale GIS and digital earth. In order to improve scientific decision－making and agility of flood prevention and the construction efficiency of flood prevention information system based on GIS,the flood prevention information system of Xianning City based on the new theory was developed. The system employed the vector－grid coalescence technology with DRG as the context reference and followed the technical route that the consumer can label the symbol of special entity at any time. The system offered an advanced technology for the flood prevention of Xianning City, obtained satisfactory results,demonstrated that the theory and technical route mentioned above have good prospects for carrying into execution. 