中文摘要：

近年来，我国测绘部门完成了国家级基础地理信息数据库的“初始建库”，基础测绘工作重点已转向持续更新和灵性服务。未来的基础地理信息“应需适时更新”将体现更新内容灵性化、更新周期适时化、更新方式多元化等特点，其主要业务模式包括变化监测、变化测定、主数据库更新和产品更新及服务四大部分。为了有效开展“应需适时更新”，应构建包括动态监测与数据预处理、变化信息采集与处理、数据库与产品更新、更新信息网络化服务四大主体部分的动态更新技术体系。该体系是信息化测绘技术体系的一个重要组成部分，应加强对其关键技术的研发，开展技术装备成套化和业务体系建设。

英文摘要：

Continuous updating and flexible service has become the major tasks of the Chinese national mapping agency who has set up national 1：50000 fundamental geographic databases. This paper gives an overview of the future ＂On demand and timely updating＂ which is characterized by flexible contents, appropriate period and integrated approaches. There will be four important phases, such as change monitoring, change detection, database updating and products renewing. Such an ＂on demand and timely updating＂ will require a strong and efficient production system. It is proposed by the authors to develop a dynamic updating system with four major components, including dynamical monitoring and data pre-processing, change information collecting and processing, updating of databases and products, internet-based updates propagation and information service. The new system will be one of important parts of the socalled informationized survey and mapping system. Key technical issues related to the development of the system are also discussed in this paper.