
Special considerations in Singapore
Singapore is a small, highly urbanized country. Because of this, there are some special considerations of note before considering using GPS in Singapore.
High density of tall buildings
Singapore has tall buildings both in residential and commercial areas. Tall buildings block GPS signals from reaching your device, and these result in a high incidence of signal loss or signal degradation, resulting in either inaccurate positioning or total positioning failure.
Singapore has a relatively organized road system
Singapore's road system is relatively systematic, with good signage. And being relatively small, a GPS may not be worth the cost or time investment to learn for many drivers. However, Singapore's immediate neighbor, Malaysia, has a wealth of roads and attractions which may not be so easily accessible. So frequent visitors to Malaysia may find GPS incredibly useful.

Singapore and Malaysia are lucky to have very well-established community maps available for free, which you can find here. Unfortunately, these maps work properly only on certain GPS devices, including most dedicated Garmin units and most Windows Mobile and Palm devices (e.g. PDAs) running the Garmin emulator software. Recently, owners of the original Mapking software could also use Malsingmaps without requiring the Garmin emulator software. These free maps are updated very often by the online community, with very accurate points of interest (where to eat the best beef noodles in Malacca, for example), making them at least competitive with the best commercial maps in some areas, often better in most other areas.
Singapore is a small market
Hence, commercial map support for Singapore is relatively expensive and may not be as updated as the Free Malsingmaps version. BMW, for example, charges a cool
Some GPS devices boast the ability to use the Wide Area Augmentation System (WAAS)
This is a system of satellites and ground stations that provide GPS signal corrections, giving you even better position accuracy, in fact, an average of up to five times better. WAAS is unfortunately available only in North America, so it may not be worth shelling out the extra cash for something which cannot be used in Singapore. If one drives in the US a lot, WAAS compatibility may be worth considering, though.
Fast pace of development in Singapore and Malaysia
Rapid changes in the road transportation for both Malaysia and Singapore make it quite important to be able to maintain updated maps every six months or so to remain useful. After all, it is the new or unfamiliar roads which most people need guidance, not the old, well-established routes.
Some useful pointers
Because of these special considerations, the following tips may come in useful:
1. If buying a GPS device that is not factory-fitted into the car already, it may be worth seriously considering getting a Garmin-branded unit which can use the free community maps from Malsingmaps.
2. An advanced feature called "Dead Reckoning" may be desirable in Singapore. Dead Reckoning is a method of estimating one's current position based upon a previously determined position, or fix, and advancing that position based upon known speed, elapsed time and course. With Dead Reckoning, once the GPS signal is lost, the device can calculate your position to a fair degree of accuracy based on your last known location before signal loss while waiting to regain the GPS signal lock. A GPS device with Dead Reckoning capability will be able to offer more seamless operation in Singapore, but you will have to pay more for it. Given the frequency of signal loss in urban areas or within residential areas in the Republic, this is worth serious consideration.
3. Given the existence of extremely detailed and usable maps for free from Malsingmaps, factory-fitted GPS navigation not compatible with Malsingmaps may not be a sterling value proposition, unless one can tolerate an increasing number of discrepancies as the Singapore and Malaysia roads change more and more compared with the GPS maps frozen at the time of the car purchase.
4. Because of the frequency of signal loss, quick re-acquisition of signals will be very useful. Signal re-acquisition speed depends on several factors, including the quality and size of the receiving antenna and the sensitivity and power of the Satellite Signal Processor chip, the heart of the GPS device. Recent products like the SiRFstarIII GSD3t use a combination of advanced GPS signal acquisition strategy and high sensitivity to achieve an extremely fast GPS signal lock.
5. For a short list of GPS maps available for Malaysia and Singapore, this page is helpful with some short comments.

