Tendencies and trends in municipal GIS
Like other users, municipalities actively undergo technological and organizational changes in the GIS area. Many of these are related to very popular e-Government solutions to provide access to databases for external clients and/or public.
Some of the technological trends that can be most recognized are:
- Drive for open standards and interoperability (organizational, technical and semantic)
- Demand for secure Web-based solutions (intranet and Internet)
- Application of mobile / field-based technologies
- Increasing demand for 3D visualization and data
- Increased importance of aerial, satellite and terrestrial imagery
- Need for cost-effective CAD and GIS convergence
- Drive for systematic and effective updating of data and information
The GIS Section at the Planning and Surveying Sector, Abu Dhabi Municipa-lity is currently outlining their development strategy in this regard for the coming years. Al Ain Municipality is also demonstrating similar approach.
GIS at Planning and Surveying Sector
GIS is used at the Planning and Surveying Sector, Abu Dhabi Municipality for various purposes. GIS Section is responsible for all topographic data, including orthophotos, plots, and approved utility lines, apart from maintaining applications. The summary of major functions supported by GIS at Abu Dhabi Munici-pality, UAE is illustrated in Table 1.
Table 1: GIS functions in Abu Dhabi Municipality
The GIS installation consists of more than 60 graphic stations, based on Unix (Solaris) or Windows OS and distributed through several floors of Planning and Surveying Sector. The database is stored on the main server in Oracle (8.05) db with spatial functions coming from SpatialWare of MapInfo Corp. Users access above data using applications developed internally (TCL/TK) for viewing, editing and plotting. MapInfo Professional is also used to connect to database and use the data for thematic output, spatial query, transformation or other sophisticated tasks (Fig 1).
Base Mapping for Abu Dhabi Island was done in 1992-1994 within Interactive Graphic Data Management Systems (IGDMS) Project by photogrammetric methods. 1:6,000 aerial photos and data were compiled to suit the 1:1,250 scale of output (Fig. 2). Positional accuracy for well identified objects (e.g. buildings, road edges, etc.) is +/- 15 cm. Large number of new attributes were collected from field verification work (especially for buildings) and input to the database during the Base Map Updating Project (1999-2000). For the mainland, existing Base Mapping information is created at smaller scales and largely out-dated.
New Base Mapping is highly needed for both areas. Also, a new system of reporting and recording all the changes by the contractors and concerned governmental departments (investors) is being planned.
Fig 1: GIS solution schema at Planning and Survey Sector, Abu Dhabi Municipality
Utility database for Abu Dhabi Island was created during IGDMS Project (1993-1994). Graphics and attribute information were taken from ‘As Built Drawings’ from different utility agencies. Using existing dimensions and construction methods, the network of all underground pipelines and cables was established (Fig 3). Water pipelines, telecom and electrical cables were detected and the database updated through Utility Detection and Survey project (1999-2001).
Since 2001, services, approved by Utility Coordination Section, are updated in the database by GIS Section staff.
It is planned that Utility Agencies will be responsible for updating their information in a common database. Initially, they will adjust their records to the existing Base Map information. At the same time, the locations of all newly constructed utility objects should be surveyed (according to accuracy standards) and uploaded into the common database. Ultimately, direct online data exchange method should be adopted.
In the mainland, no digital database exists for utility records. Utility Agencies, operating their own GIS systems, have no information satisfying accuracy standards required by Planning and Surveying Sector. This fact and the lack of the updated Base Map make planning activity very difficult.
Abu Dhabi Island planning database was created during IGDMS Project (1993-1994). Planning drawings, referring to road centerlines, were used as a data source (Fig. 4). This part of the database is continuously updated by Planning Section staff.
Fig 2: Software and Base Map sample of Abu Dhabi city. Source: Planning And Surveying Sector, Abu Dhabi Municipality
Fig 3: Utility Data sample of Abu Dhabi City. Source: Planning And Surveying Sector, Abu Dhabi Municipality
In 2002-2003, GIS staff entered owners’ names information in Arabic with help of dedicated application. This cadastral register is maintained regularly, on daily basis, by local staff. No digital planning data and owners’ names are available for the mainland. There are only sets of Planning Drawings in analog format and some digital data for newly designed areas/cities.
Abu Dhabi Island control network was created in 1992 for IGDMS Project and consisted of approximately 450 points, well monumented, surveyed (GPS campaign) and described. It is considered as a 2nd and 3rd order control with accuracy +/- 1 cm. This network is the subject of continuous damage due to huge construction activity on the island. The network was largely updated and reestablished (approx. 35% of points) in 1999 – 2000. So far no maintenance mechanism is adopted.
In the mainland, Geodetic Control network was created for Aerial Mapping Project in 1988. Vast majority of points already does not exist. Establishing Active GPS Ground Reference Station network should ease the problem.
For the Capital Region (4,500 sq. km.), ortho-rectified photo imagery was acquired in 2000 (high quality, good accuracy of locations, pixel size 0.75 m). The whole Abu Dhabi Emirate was covered by new satellite imagery in October 2002 (IRS data, color rectified imagery, pixel size 5.0 m). Satellite images, covering parts of the Abu Dhabi Island and Emirate are also available with various Departments. High resolution of orthophoto imagery (10 – 20 cm) is expected to be procured in the future mapping projects.