Comment by sideproject | Hacker News Reader

Comment by sideproject | Hacker News Reader

I had a similar experience about a month ago, when I thought I lost my iPhone 5s.

Logged onto "Find my iPhone" app and it told me it was about 1km away from my house. I thought I must've dropped it somewhere nearby.

So I got the address from Apple Map, drove there and knocked on the door to greet a rather defensive (obviously) lady who, of course, denied ever picking up an iphone that day.

I snooped around to see if there were any suspicious people around, maybe she has a wayward son who goes around and steals other people's phones.

I then went to the police office nearby and asked them what I could do. They told me they can't use the GPS tracking as an evidence for a search warrant - doh!

It was frustrating because the app was telling me that my phone was right there! At the back of this lady's house!

At this moment, I was going through all sorts of thoughts - such as "should I break into her house at night?", "should I go back and just barge into her house and locate my phone and shout 'AH HA! I KNEW IT! YOU THIEF"!

Feeling dejected, I came home, only to find my phone sitting on the top of my drawer.

2 seconds ago, I swear I thought she was the thief.

Apple - you disappointed me.

Find My Iphone has a ring option. Always try that first

When you went back home did you check and see if she was following you? Maybe she snuck in and replaced your phone.

out of curiosity, does it only show you a single point? Does it not show you the potential error?

I'm working on a mapping app that uses GPS data and the first thing we had to address was the fact that the data we got from the GPS units in the field are not perfect, they have error, hell they report their error, and our application shows that error as part of the map data.

based on the data we have gotten from mobile phones, when a phone approximates its position based on cell towers it spits out a large error. That surely is being shown, right?

Does it not show you the potential error?

I often use Find My Friends to keep track of the kids. I presume its location methodology is similar to Find My iPhone. Here's how it behaves:

About 10% of the time, it doesn't show a current location at all for the kid. It does remember the previous one, so it will show a location and say something like "46 minutes ago".

When it does display a location, about 60% of the time it's a single spot.

The remaining 30% of the time it is a spot enclosed by a tinted circle. That circle can be a few hundred feet in diameter, or it can be more than 5 miles in diameter. This is the potential error. However, I'd bet that 95% of the people looking at it don't understand the concept of "potential error". So to them, the enclosing circle doesn't exist.

Edit: forgot to add, about 2% of the time it will show an "exact" location, what I called a "spot", no "potential error" circle. Then a minute later it will show a different exact location a few miles away. Then a minute later yet a third exact location another mile or two away. So in other words, about 2% of the time it is really confused (the kid is stationary the whole time).

Thanks for the response, we've seen this behavior indoors. It may be that some applications will choose to show a single point if the error is below 20 meters or so. Looking through a record of our location updates, iPhones seem to have a habit of broadcasting 5 meters error, 10 meters, 20, and so on. Even when indoors.

We don't have as much data on android phones yet.

You're right about how the laymen might interpret potential error. The team I'm on is also concerned about that, but I know on the android that as the map tries to find your location through GPS, that it displays a large radius approximating your location through a cell tower, and I had always figured that would communicate the notion of "error" pretty clearly to most people. Maybe most people don't pick up on that?

By the way, The largest error we have received so far seems to be at 2015-11-17 23:11:11.421.

33149.68 meters large

"So I'm sooomewhere in this 33 kilometer radius"

Better than nothing I guess!

> The remaining 30% of the time it is a spot enclosed by a tinted circle.

That's the way I've always seen it, and I think it's a UX error. As you say, most people don't even see the circle as the potential error in accuracy. IMO it should be just the enclosing circle, otherwise people only see the point; with just a circle there's less ambiguity.

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