Hi There:
That's a tough question. Garmin themselves don't make any maps, nor do they collect any kind of mapping information. Garmin is strictly a hardware company - they make GPSRs. Garmin contracts with other companies - notably Navteq, which is a huge Dutch company - to provide them with cartography in a format that is compatible with the Garmin GPSRs. Garmin then sells this cartography under their own name, for example, as "Garmin City Navigator Europe 7".
All the major automotive companies do the same thing - they buy their cartography from a cartographic specialist, and sell it under their own name. I own a Volkswagen, and the OEM nav system in my Volkswagen runs just great on BMW navigation CDs, because the same company (Siemens) makes the nav hardware for both carmakers, and the same company (TeleAtlas) supplies the cartography.
OK - having said all that - the question still remains, why is cartographic coverage of 'Country X' still incomplete, poor, filled with errors, non-existent (choose applicable complaint)? To comprehend this, you need to comprehend how the cartographic vendors (TeleAtlas, NavTeq) get their information. For the most part, they buy it from the governments. If the government of a certain country already happens to have a very complete, accurate, and highly detailed GIS (Geographic Information System) in place, then voila, we get awesome maps. Switzerland is an example of this - not only is every single road present on the CN maps, but also every pedestrian path and every cowpath. That ain't the doing of Navteq, it's the result of many years of work by the Swiss Federal Office for Land Topography, whose copyright appears on the work (and, on you GPSR at boot, if you look closely enough). You can bet the governments - every single one of them - charge for this data. This is why European cartography is so expensive, compared to North American cartography. There are about 15 different governments to be paid in Europe, and only 2 in North America.
What the cartography companies then do, in situations such as Switzerland, is they drive around and 'add value' to the government provided data, for example by noting the speed limits, traffic lights, the exact wording on overhead signs, stuff like that, and adding it to the product.
Getting back to Northern Ireland - I can only guess that the government there does not have all the roads in the country entered into a GIS, and as a result, the level of detail in what they can sell to the cartography companies is limited. Adding to the problem is the fact that Northern Ireland is fairly sparsely populated (compared to, for example, Netherlands), so the cartography companies don't have a market-driven reason to get out there and fill in the gaps themselves.
Not much you can do but wait. Last time I was in Northern Ireland (2001), I was using MetroGuide UK version 2 or something prehistoric like that, and I got lost on Shankhill Road and went into a pub to ask for directions. Seems they are all motorcycle enthusiasts along that street - first question they asked me was 'What foot do you kick with?' I told them that the Honda had an electric starter.
You don't really need maps in Northern Ireland anyway - just look at the flags hanging from every building, from that you can easily tell what part of the town you are in.
Michael
