Getting there

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Dear TPH,
Do you know where I could buy a GPS navigation system with Sri Lankan road maps?
– K.H.

Dear K.H.,
If my answer to your simple question was in fact a live cricket commentary, this would be the point where Tony Greig would barge in and say "I presume you are not from this nick of the woods, mate". And, "One would like to see the day when expensive cars on our roads would have GPS navigators that actually work – ones that actually have our road maps that have mapped the road," would be Ranjit Fernando's reply. At this point, you, and millions of other viewers across the world would be dumbstruck and confused as to what that last statement actually meant.

Of course, these days GPS navigation systems are not a luxury limited to expensive cars. There are cheaper, standalone GPS navigation units that you could fix on the dashboard of your car. Nokia recently released its new 6110 Navigator phone; it's a 3G phone that includes GPS navigation capability.

The mapping data and other points of interest (POI) for a GPS navigation system has to be plotted and installed in a navigation device for it to be of any use. Usually, this mapping data is captured by someone driving around the roads with a differential GPS receiver; a more accurate version of a standard GPS receiver thanks to additional position correction circuitry. Differential GPS needs to be licensed from the government. The advantage is that it is accurate to within 50 centimetres (as opposed to standard GPS, which can be accurate from one to ten meters depending on atmospheric conditions), and it provides both coordinates and a clock pulse to a laptop. The pulse cycles at about 1Hz and can also be used by the laptop to capture images every second with the reception of GPS coordinates with a roof mounted camera to produce a similar image to Google's street view. All roads are plotted by driving through them, and subsequent drives have live co-ordinates layered over existing maps in real-time. Any changes, such as roundabouts replacing intersections, are tracked by the computer operator. The driver would then circle the roundabout to map out the changes in the road and then verify the new information against the photographs back at base. This new information is then sent back into the database and rolled out as part of the next update.

The process is surprisingly labour intensive and costs a lot – not to mention the bureaucracy and legislative restrictions. Almost all points of interest are entered manually, including restaurants, petrol stations and local street rules. The system has the capability to apply local street rules to different vehicle types. For instance, a street that is off limits to heavy vehicles would receive a database entry that would make the route inaccessible to trucks. I have no way to confirm this, but these factors may have contributed to the delay in the mapping of Sri Lankan roads so far.

To answer your question more directly K.H., I do not yet know of any available set of GPS enabled maps that cover any Sri Lankan cities – let alone all Sri Lankan roads, but I would invite any readers who know of any such available maps to write in to technopage@gmail.com and share the news.

– TPH