Wrong locations when storing GPS / My Places on Mallorca
  • Vote Up0Vote Down udippeludippel
    Firstly, congratulations and thanks for a great and useful application!
    I personally consider the use as something one has to get used to; but that's no complaint.

    Recently on Mallorca, however, I was mislead by the navigation. I can confirm that it was repeatable, and so far inexplicable for me. We arrived at the center of a city (Alcudia) by bus, the map showed me that location, it was correct, and then I saved it in 'My Places'. Later, I discovered a nice restaurant, and did the same. Then, I set the bus stop as navigation target, and ended up elsewhere. I mean, I ended up where then target was on the map, but that was not the earlier bus stop. I checked the location of that restaurant, and it was likewise shifted close to a km to the east. The same had happened with the bus stop. I did a third trial, and stored the current GPS location under My Places, and then looked it up on the same map immediately, and it popped up close to 1 km to the east. Hmm. So that's what I could confirm yet again: I am shown my proper and correct coordinates, and when I store them, whichever way, the target icon, when called up later pops up at a significant shift. 
    I had also tried the odometer from the restaurant to the bus stop, and its locations and path were totally correct: from that restaurant to a location that was close to 1km from the bus stop, though on the map it was exactly having reached the target icon.
    From all these I can only assume that under those circumstances the only, but consistent, error happens/happened when storing either a location as such or the current coordinates. With, as result, a constant shift of that location w.r.t. its coordinates compared to the original ones that the machine has been able to identify perfectly well. So I assume that the problem was with the storage. 

    I hope that this is helpful enough to correct this for future uses/users. I am running 1.3.43 on Android 4.1.

  • 3 Comments sorted by
  • Vote Up0Vote Down mdxmdx
    Hi udippel,
    did you use also WiFi network for localization? I tried 1.3.43 with GPS only and it worked as expected - the position error for GPS is typically smaller than for network ... so I am not sure what could be the problem. Can anybody else confirm the same bug?
  • Vote Up0Vote Down hvdwolfhvdwolf
    I can't confirm this but normally when using Wi-Fi you are talking about A-GPS. A-GPS is only used if you have only 2 GPS locations, which means that you need the WiFi position as 3rd position. This gives you an estimated accuracy of 10-50 meters.
    As soon as you have a 3rd GPS position the WiFi position is not longer used and your position will become more accurate when you acquire more GPS locks.

    Anyway: a 1 km offset can't be the result of "normal" GPS versus A-GPS.
  • Vote Up0Vote Down udippeludippel
    Guys, no, I don't think so. Firstly, I wasn't connected to any WiFi, since we had just been hopping off a bus; and most - if not all - WiFis there were protected.

    What strikes me is not a lack of accuracy; as I said, the indicator on 'Map' was exactly correct (okay, maybe within 10 m). And my odometer gave me the exact path that I had walked. 
    What *was* wrong, was alone the position that was stored under 'My Places'; and it was reproduce-ably wrong, by (I guess) always about the same distance and direction. I could add a screenshot if necessary. 

    Maybe I use it in an unusual manner, but I have stored quite a list of 'My places' in Germany and The Netherlands, and when I called them up later, the target flag was positioned exactly where I had stored the respective position. Not so in this case, in Spain (Mallorca). 
    (My wife was even sore, since we had hopped off the bus, and agreed to meet there at the bus stop some hours later, I had shown our location to here, it was obviously correct on the map, I saved it as 'Bus stop Alcudia'. Some hours later, I selected it as target for 'Navigate', and when I arrived there, at the position of the flag, it was around 1 km away from the bus stop. No wife, totally elsewhere. Then I used just the map to walk back to meet my wife. And then, in Alcudia, I could repeat this behaviour a number of times. We went to a restaurant, Garlanda, and I saved the position. Directly. Then, when i want to 'My Places' it was vastly elsewhere (I guess around 1 km). I saved it under a different name from the 'current GPS coordinates', and it was away around one km, overlapping with the earlier one. No way to store the correct, current location. However, I started an odometer session, and when we arrived at our hotel, the odometer session of that day indicated the exact location (address) of restaurant Garlanda, and our way back to the bus stop that we had intended. 

    A very long story (I don't know if anybody read until here), though I wanted to stress my point that the accuracy of the GPS was totally correct in all cases, only the stored (or retrieved) locations from under 'My Places' was seriously off in all trials.
     
Add a Comment

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

Sign In Apply for Membership

Categories

In this Discussion

Tagged