There are lots of great stories about people finding their lost iPhone by using the Find My iPhone feature available to subscribers of MobileMe — sometimes because the iPhone is stolen, but often just because a person cannot remember where they left it. As useful as Find my iPhone is, be aware that if you find yourself in a tall building, the feature doesn’t work very well.
For example, my law office is on the 46th floor of One Shell Square. When it was built in 1972 it was the tallest building in the entire Southeast, and it remains the tallest building in New Orleans. From my office, I have a great view of the city and the Mississippi River, but that high up I don’t have great AT&T reception (although it is much improved with the iPhone 4). Here is a view of the Mississippi River and the Warehouse District in New Orleans, taken from my office using an iPhone 4 (click to see the full size, original file):
The Find My iPhone feature, like the iPhone Maps app, uses GPS and cell tower triangulation to determine where you are located, but I suspect that it presumes that you are at ground level because whenever I am on the 46th floor of One Shell Square or any other tall office building, I find that Find My iPhone is really off. For example, here are two recent readings when I was sitting at my desk in my office. My office building is located where I placed a green rectangle with arrows pointing to it, but my iPhone thinks that I am located many blocks away. In the first picture (using Maps), it thinks my iPhone is close to where the New Orleans Convention Center is located. If I didn’t know better, looking at this map I’d think that someone in town for a convention had stolen my iPhone. In the second picture, taken a different day (using the Find my iPhone app), my iPhone is supposedly on the other side of the Superdome from my office.
If you subscribe to MobileMe and you lose your iPhone, by all means use Find My iPhone to try to locate it. But just keep in mind that if you lost your iPhone on the upper floors of a skyscraper, you can’t trust the Find My iPhone map.
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Jeff: I have experienced this phenomena as well. As an experiment, try turning off your WiFi and see if the accuracy of the locator function increases. I find that when I am on WiFi here in my office building in midown Manhattan, the accuracy is often a block or two (sometimes three) off; but when I use 3G, however, the accuracy (of both Maps and Find My iPhone) improves markedly.
Why is iphone able to receive and dial calls when mobile me can’t find that specific same iphone? Yes, I work in 12th floor yes as well.