Is the GPS on the Nokia900 as good as something like a proper TomTom car sat nav device? Or is the GPS on mobile phones usually a lot worse?

Also how does the GPS compare to other phones?

http://www.nokiausers.net/N-Series/O...-N97-5800.html
this video might give you a few answers but remember the n900 is a preview unit up against full commercially released units.
I have also read people saying on twitter saying GPS on n900 is awesome

There is no digital compass, so it is not possible for it to be quite like a TomTom, where it gives you directional voice instructions. It's a 2D map rather than 3D.

I've found the GPS hit and miss.

If there is a web connection it's fast, but I've not had the chance to try it on a 3G network yet though. So have no idea if the 'network positioning' through the location server will work on that as well as a fixed internet connection.

The effectiveness of GPS on phones varies between phones. (Some use pseudo GPS based on triangulating on the cellular network tower.) I found it more 'accurate' than the e71. That is more precise and often less of a vague red blur of a position that the e71's software was giving me.

I think the ovi maps software could be better bundled. The software updater should prompt a link to download the 'map loader', which is nice when roaming -- as you can download on the cheap to your PC and not on the roaming charges.

What is annoying about the n900 is that it will keep asking to select connection -- I assume because I had left 'network positioning' on. But I haven't tested this.

S60 phones seems to be able to give you directional voice instructions perfectly fine without a compass.

I am however very surprised it wasnt included in the N900, for maps and especially augmented reality.

There's no need for a digital compass for that, and the TomTom devices I'm familiar with don't have any. There's an accelerator detection device in stand-alone units though, but it's only used for dead reckoning - i.e. giving some kind of tracking when you're driving in a tunnel.

I use TomTom on a Palm PDA, and you get directional advice/turn-by-turn descriptions because you're in motion, and when you're in motion a standard GPS receiver is sufficient.

EDIT: A digital compass is still very useful though, and indeed a must-have for any kind of augmented reality apps.

I assumed that TomToms must have a digital compass, as my TomTom ONE knows when I have made a U-turn.

It's still a 2D overhead view on the N900, and not a angled 3D view like on a TomTom, am I right?

As long as you're moving your GPS is sensitive enough to know that you're U-turning. It works just fine on my PDA which doesn't even have an accelerometer. There's one in your TT One though. [EDIT: Actually I can't confirm this. There were some GO models without an accelerometer, and I can't at the moment say for sure that there's one in your One. In any case you don't even need anything else than just the GPS for turn-by-turn (or U-turn) navigation. My PDA tells me when I'm at the correct part of the roundabout to leave, for example.]

Other's will have to answer the 2D vs. 3D question though, but in general there's not many navigation applications around that are up to TT standards

Default, 2D view:


3D view, toggled via the on-screen compass:

I believe the Tom Tom software would work very well on the N900 if it were available for the N900. Garmin, Route 66 and many other GPS programs are available for S60 phones. I believe they will be ported to Maemo as Maemo becomes more common. Tom Tom is available for iPhone and Windows Mobile. Someone should ask them to develop a version for Maemo.

A compass is very important if you are standing still pointing your phone at things in augmented reality. But for driving directions the GPS knows what direction you are moving.