OpenStreetMap 開放街圖
I have been trying out a Samsung Galaxy Y Duos with Google Mytrack the last days. The accuracy of the recorded aGPS data changes somewhere between 3m and 20m radius of the actual position in mid-town area, which is pretty useless for finegrained recording, I would say. I guess open terrain data would not be much better in areas with large phone cells for the network assist. I just ordered a dedicated Visiontac VGPS-900 data logger for further track recordings, so next week I will do some track recording with both devices to compare accuracy.
討論
由 robert 於 2012年08月13日 00時14分 發表的評論
“The accuracy of the recorded aGPS data changes somewhere between 3m and 20m radius of the actual position in mid-town area”
Err.. in a mid-town area I wouldn’t expect significantly better accuracy from any consumer-level GPS device. No matter what it claims.
由 asgalon 於 2012年08月13日 12時41分 發表的評論
I’ll make some comparisons with both devices active in a couple of days. It already looks like in small parks and open areas like at the beach the accuracy is much better than between buildings. I actually came to participate because I am developing a mobile application with mapsforge which will be mainly used in the town area with Android smartphones, so I was wondering how well this would work locating the position with GPS receivers used in normal mobile phones. I already saw that you can get a general idea where you are and fix the exact position using the map if there are sufficient details, but for recording mapping information it seemed a bit coarse. So probably this investment was absolutely superfluous, but that too would already be a result worth noting… So, more of that next weekend when I can compare tracks.
由 robert 於 2012年08月14日 16時47分 發表的評論
Yeah, GPS in cities (especially with mobile phones) is… variable.
Either way, the VGPS-900 serves as a good “baseline” for the results to be had with a reasonably good receiver.
由 asgalon 於 2012年08月18日 21時32分 發表的評論
Oh, I did not take into account that in August EVERYBODY is away for vacations. It looks like they were in such a hurry to get away that they forgot to put a note at their online shop that orders are pretty useless until september…