Low cost GIS data base solution for water utility network in Sri Lanka

In 1999 National Water Supply and Drainage Board (NWSDB) commenced developing a Water Utility GIS for the Greater Colombo(GC) area with the objective of improving its operations and maintenance activities. National Survey Department of Sri Lanka was contracted out to produce 1:1000 scale 3D digital base maps from Air Photographs. Available water utility maps were digitized using Autocad Map GIS and updated using Global Positioning Systems and other survey methods. Due to voluminous nature of base maps and utility data it is impractical to store them as a one seamless coverage. Storing these data as separate map tiles leads to several practical constraints such as updating difficulties, searching delays and data retrieval problems. Therefore it is required to develop a Geo-database to efficiently manage these data. It is not feasible to utilize available commercial Geo-databases for this purpose due to their high purchasing and maintenance costs. As a solution PostgreSql, a free Open Source Object Relational Database Management System(ORDBMS) was selected. PostgreSql has a module called PostGIS which handles spatial data and is used by hundreds of similar organization around the world. The software successfully runs on Linux Operating System, which also is a freeware. Geo-database was established in PostgreSQL ORDBMS with necessary table structures, relations etc., to store and manage geometric/attribute data of water features including 3D basemap data. A user friendly interface was developed within Autocad Map GIS to handle data uploading and retrievals. All necessary procedures were introduced to the organization for the efficient management of the Geo-database. Further, an Intranet Web Map Browser was developed to browse the data. Currently the system has 18 themes with total objects of around 800,000 and successfully used by all Water Manager Regions in GC area for their day-to-day activities. This implemented solution provides an excellent platform for the NWSDB to do advance geo data management for low cost.