ISPRS, Vol.34, Part 2W2, "Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001 
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ENHANCE MANAGEMENT LEVEL OF URBAN WATER SUPPLY DEPARTMENT WITH 3S TECHNOLOGY 
Yewen FAN 1 and Wei WANG 
1 .Information Engineering Center, Wuhan University, Wuhan, China, 430079. 
Te!:+86-27-87643969, +86-27-87665485. fyw@geostar.wtusm.edu.cn 
2.LIESMARS, Wuhan University, Wuhan, China, 430079. 
Tei:+86-27-87643969,+86-27-87665485. wangwei@rcgis.wtusm.edu.cn 
KEY WORDS: GPS, RS, GIS, routine surveying technology, carrier phase differential 
ABSTRACT: 
The Urban Water Supply Company mainly deals with the underground duct system. However, due to various kinds of reasons, the 
underground duct systems of each Urban Water Supply Company are of bad actualization and low precision. They can hardly give 
optimal play in practice. Therefore, it is essential to increase the actualization and precision of the underground duct system as well as 
the management level of the Urban Water Supply Company. When GPS is carrying out false-distance differential, adding the corrected 
value of carrier phase differential will increase the real-time positioning precision to the level of CM. Combining the RS technology at the 
same time, it is able to obtain the 3-D coordinate of the underground duct system accurately. Applying GIS technology in the water 
supply industry, the application analysis function of the industry will be enhanced so as to manage the urban lifeline - underground duct 
system information scientifically. 
1. INTRODUCTION: 
At present, Geographic Information System (GIS) has been 
widely used in the field as land management, city planning and 
mine prospecting. Its application in data management, data 
development, spatial query and spatial analysis has been 
recognized by more and more people and acquired attention by 
more and more departmental leaders. Though GIS is just a 
fundamental platform of fundamental geographical data 
management, leaders and technicians are exploring and 
studying on how to combine GIS with each industry application 
so that GIS can become an information system for a profession 
and serve for the profession more effectively. 
Global Positioning System (GPS) is established by the US 
Department of Defense aiming at contenting the demand for 
carrying out maritime, terrestrial and air navigation and 
positioning with high precision by the military department. By 
adopting GPS technology, there is no need for the mutual 
vision among stations. It is able to carry out high-precision 
positioning round-the-clock with convenience and high 
efficiency. With the rapid development of GPS technology, GPS 
precision positioning technology is becoming mature and has 
been widely used in the field as economic construction and 
scientific technologies. 
Remote Sensing (RS) is a high and new-technology industry 
studying on how to obtain relevant attribute of the objects 
without direct contact. By sending and receiving 
electromagnetic wave reflected by the objects or receiving 
electromagnetic wave sending or reflecting by the objects, RS 
technology studies on much attribute information as existent 
state, texture and characteristics of features as land satellite, 
meteorological satellite, aerial photography, radar and survey 
meter so as to identify them and reach the goal of cognition. 
3S technology is the integration of GIS, GPS and RS. As GIS, 
GPS and RS have their own characteristics respectively, it is 
difficult to meet the demands or solve problems in practice by 
using only one or two of the three technologies. Commonly, to 
integrate the advantages and characteristics of the three 
technologies is the key to solve the practical problems. Duct 
system is an essential infrastructure of the city construction as 
well as the blood and lifeline of a city. It spreads over every 
corner of a city and forms an underground network in a 
crisscross fashion. However, in China, the duct system of most 
cities has a long history. They are of various types and a great 
amount. Over a long period of time, due to many reasons, the 
duct system is in serious lack of fundamental materials. The 
pipeline materials as valves are of bad actualization. The 
blueprint and practical situation are unmatched as well as the 
positioning error is big, which brings great difficulties to the duct