The difference is that while it is unclear what method Google use, Navizon clearly states they will PAY users who have GPS installed in their phones, to roam around and collect Cell ID, APs, etc. and submit it to them. At the SAME time you get maps to see where you are, Buddies to see where your friends are, etc.
So in this instance, Navizon is paying for the crowd to submit the latest/updated data all the time. So if I drive around an area, and an AP that was there yesterday is no there anymore, you won't get the same error as Google where you suddenly appear to have gone to a different city/state/whatever, as I just personally updated the AP landscape.
Great stuff, and to get paid as well... I guess it is cheaper for Navizon to pay users a $10 or $20 dollars for a few hours of "driving" rather than run their own vans around trying to update APs all over the world, and this way the database is likely to stay very, very fresh!
Problem is, he doesn't specify which labs use more SNPs or "more useful" SNPs (which as you mentioned, should provide better/more accurate results).
The point of experiments and tests should be to draw some conclusion (even if the conclusion is that all fail) but clearly some services are performing better than others and are turning out more accurate. Why does he not state, in his professional and unbiased opinion, which one is better?
So which service produces, in his expert opinion, the better overall results/conclusions/advice?
I RTFA and fail to see what the pros/cons of each service is, and which one he recommends.
I know that would be a boon to whichever company is producing the better results, but who cares? If he is suppsoed to be independent, what does it matter if he gives his honest opinion?
Well, I created a system to track my car wherever it went, not quite tracking a kid, but to some people, almost as important
Navizon actually is a good service. You make money on it if you have GPS attached (yes, that is a referral link, but bear with me a sec), but that is besides the point... GPS doesn't work in an urban jungle, and from my experience, parking my car in a multi-storey carpark and near the edges (so the GPS is could sort of get a line-of-sight) still wasn't good enough for GPS to work constantly.
So the way I use Navizon, is that you can set it to output its multi-tracking (GPS, then WIFI, then Cell ID, in that order, as each is less successively less accurate) service to a port on your device, and let OTHER GPS-related programs access that port, so when GPS is out-of-sight and not working, your GPS application continues to get relatively accurate positioning based on WIFI, and then failing that, triangulation based on the Cell IDs.
They also recently added in Fireagle (the Yahoo service) so that you can update your location via Twitter and whatever else works with Fireagle. And Navizon has it's own API besides Yahoo's open API if you want to play with that. So since you wanted to write your own app to view it on a website/domain (which you can either use very simply on Navizon's own site, or if yo want to get fancy and update via Twitter or others services, Fireagle integration) then you can.
I even though, if people put my car into a warehouse or even inside a container, at some point during it's travels, even if its sealed, it hopefully would get at least a Cell ID or Wifi position, so even without GPS it'll be functional. It won't be hugely accurate, but it'll set you in the right direction at least. And it doesn't rely on any carrier either, so it's carrier neutral too.
There is no royal road to geometry. -- Euclid