Question about GPS accuracy and the iPhone 4
I've been an iPhone 4 user for just about a month now, and noticed something that I'd consider a bit odd... When I use apps that need to know my location, the information I get back from my iPhone 4 seems to vary a bit at times. I'll give an example... I was traveling from downtown Seattle to my house in the southwestern part of the city, and since the bus I was riding on didn't have a properly functioning automatic stop announcement system (it calls out most stops with a recorded voice, useful for a blind or visually impaired person like myself or those unsure of the stop they might need), I used one of the navigation apps I had installed to make sure I got off at my stop. For the majority of the trip, nothing seemed amiss, but once I got close to my house (within 300 feet of the corner nearest my house), I noticed that the information I got from the app was slightly inaccurate. Instead of informing me that I needed to turn in 300 feet or so to arrive on my street, it told me to turn immediately to the right to arrive on my street... which if I had followed the iPhone's directions blindly (no pun intended), I would have wound up in someone's front yard. I did continue to what from what limited vision I do have, what would be the intersection and made the turn down my street toward my house, but before I could get more than a few feet down my street, the iPhone informed me that my destination was on the left. Of course, this was wrong, as consulting the Compass app when I got home, I discovered that my house is actually 219 feet from the corner, roughly about mid-block.
I'm not sure if Navigon was at fault here, or the GPS hardware in the iPhone isn't working right, but I do have to ask, since apps like Foursquare seem to be a bit more accurate most of the time. I wonder if it could be the way I'm holding my iPhone, a misbehaving GPS chip, or some weird fluke of my neighborhood in Seattle (it's fairly close to a small airport, but sits considerably higher in elevation). Anyone else out there having issues with the accuracy of information their iPhone gives them when using GPS, or is it just me?