In April 2006 at a conference organized by PDS on Pangkor Island in Malaysia, Professor Alias Abdul Rahman from the Universiti Teknologi Malaysia talked about 3D cadastres, which are more important in Asia, where urban population densities tend to be higher. Professsor Alias outlined three approaches for dealing with 3D cadastres
- Administrative tag model - Integrate 2D spatial with tagged information for strata
- Hybrid model - Integrate a 2D cadastre with topological information about 3D structures
- Full 3D model- Requires a complete overhaul of the cadastre to incorporate three dimensions
Professor Alias had developed a pragmatic solution based on the hybrid model that supported topological queries including adjacency using off the shelf products (COTS), for example, Oracle Spatial and AutoCAD Map 3D.
Singapore's motivation for a 3D cadastre
Yesterday at the Asia Geospatial Forum conference here in Jakarta, Soh Kheng Peng of the Singapore Land Authority, which is reponsible for the cadastre (parcel fabric) in Singapore, gave a riveting presentation on the reasons for the importance of a 3D cadastre in Singapore and what the Singapore Land Authority is doing to implement a full 3D cadastre.
Defining the 3D cadastre problem
Soh Kheng Peng made it very clear that a 3D cadastre is in the cards for Singapore, for several reasions.
- Land developers are being very creative and packaging complex volumetric parcels both underground and above ground.
- Current survey techniques cannot capture accurate 3D coordinates.
- The current 2D GIS used to capture and store cadastral information is unable to represent volumetric parcels.
- All strata boundaries are not in the cadastral GIS, making it impossible to perform effective spatial planning for national development goals.
Underground space is heavily used and underground density is increasing. Underground lots are getting very close to each other and accurate delineation of boundaries is required.
First step toward a full 3D cadastre
The Singapore Land Authority has identified priorities for the first step toward a 3D cadastre. The first priority is to change survey procedures to enable surveyors to capture accurate 3D information. This means adopting new technologies and changing legal requirements for surveys. The next priority is to collect sufficient information in a 3D GIS to support national planning goals.
Basis for virtual Singapore
I've blogged about other cities' efforts to create 3D urban models, for example, Vancouver, and a recent software release focussed on conceptual design for 3D urban environments. These have been undertaken for planning purposes, for zoning and other bylaw enforcement such as viewports or right to light, or one of the most remarkable recent efforts, Sydney Down Under, for emergency and disaster planning. But in Singapore Soh Kheng Peng said that the "future 3D cadastre will be the fundamental information for building virtual Singapore." This means that virtual Singapore will not only be a representation of Singapore in 3D, but will incorporate the legal 3D parcel fabric.