two dimensions out of three

[cellio]

It's funny to see (well, hear) my phone's navigator app react to parking garages. "Do X... oh ok you're going north so do Y... oh you're going west so do Z... oh you're going south do A... oh you're going east do X which I'll pretend I haven't said before..." -- iterate until you reach the exit. It doesn't respond to elevation, only latitude/longitude.

I can think of three possible reasons for this, and I wonder which it is (or if it's something else I haven't thought of):

1. The GPS in the phone doesn't detect altitude.

2. The map data (Google's, in this case) doesn't record elevation. It does you no good to know that the GPS is at a certain elevation if the app can't tell that that's 200 feet above the road, after all.

3. The GPS and map data are available, but the app isn't programmed to take it into account. How often does this really come up, after all?

Comments

[cafemusique.livejournal.com]

My impression, just looking at some of the tracks and profiles I've recorded with my phone is that the elevations reported by most phone GPS hardware are subject to a lot of error. Also, in a garage, there's an obstructed view of the satellites, so the accuracy is even lower. I am not sure that the GPS chips in phones are precise enough to determine what level of a multi-level structure one is on.

[dagonell.livejournal.com]

I would be content with "Exit from Parking Garage".

[cellio]

Good point. I wasn't thinking about "what level of the garage" so much as "are we at street level?".

Hmm, I wonder what you get if you're standing on the top of the wall surrounding Jerusalem's old city and ask for (walking) directions within. Maybe I'll remember to test that someday.