I. Introduction
Underground pipeline network (for short, UPN) is the lifeblood of urban infrastructures. It is the foundation for modern cities to run efficiently. There are many types of underground pipeline network and they change frequently, making up a maze of a large network. Studying and managing the urban underground pipeline network in a proper and efficient way will help to guarantee the quality of urban economy construction. The management of underground pipeline network has changed from the manual mode to the GIS mode in many cities in China since 1980s, symbolizing a great leap in the informatization of urban underground pipeline network management.