ASM
Street Directories in Singapore
Since 1954, the Singapore Land Authority (then know as the Survey Department) has been publishing a comprehensive street directory of the city.
Until 1995, it was prepared manually. After that, the production process went digital, using CAD software. While an improvement on manually creating the directory, this required each page of the directory, with all the different features, to be stored in its own individual CAD file.
Managing so many files was cumbersome. One technician could only make edits to the data at any one time. The publisher then scanned the hardcopy maps, painstakingly filling in every feature with the appropriate colours. The indexes to streets and places were manually entered in worksheets or text files.
To beat these obstacles, SLA developed stand-alone utilities and programs in-house for data conversion, transformation and data loading. However, development and maintenance of these diverse utilities was challenging; it required SLA to employ specialised technical man-power. In addition, transferring data from one software environment to another resulted in data losses.
Data is now stored in an enterprise geodatabase. The geodatabase is accessed using ESRI’s ArcSDE with Oracle serving as the underlying database.
SLA also developed custom data loading programs using ArcObjects, a set of programming libraries specifically for ArcGIS and .Net. The data loading programs use complex validation rules while facilitating data and updates from various sources. ArcSDE also helps define several cartographic rules such as the need for bridge symbols to always appear over roads, canals or rivers at the database level.
Once all the cartographic activities are complete, SLA uses a custom built Mapbook creation tool based on ArcObjects for laying out the individual pages of the directory. Different areas of Singapore have different feature densities; this tool helps to generate map pages at different scales. The map pages are then exported by the Mapbook utility into PDF format which is then passed to the publisher for the final printing work.
SLA has implemented two new services for public consumption as spin-off of the new digital process.
One service is an online street directory; people can search for a location using various types of searches.
A visit to www.map.gov.sg/landquery allows members of the public to obtain land ownership information for any land parcel. It also provides contact details for the land owned by government agencies for the public to contact the agency for temporary lease or to report incidents such as fire or mosquito infestation on government lands.
