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

[cellio]

Thanks for educating me!

(You may recall the days of "turn left from Forbes Ave onto S Neville Way" directions from map sites.)

I do indeed. I didn't know if the change there was due to better satellite info (or better use of it), or crowd-sourced corrections to the map set. I know I've reported bugs in directions at times and wasn't sure how those got corrected.

I don't consider this a bug at all; an app that (somehow) took this into account would get a "hey, cool!" reaction, but it's far from necessary. As I said, how often does this come up?

(I suppose detecting "driving in circles in a sub-block diameter" could provide something useful.)

[eub.livejournal.com]

By the way, to give credit where it goes, fixes to data like the Forbes/Neville grade separation were probably made by the map data vendors (Navteq, TeleAtlas, et al.) through old-school "vans on the ground", driving around and taking notes on the roads. Just by the timing, before any of the fancy stuff was around much.