aeracode / gpslogger Goto Github PK

In assessing the precision of a GPS track for mapping, HDOP is useful but is 
only part of the story. (see http://www.outdoormaps.org/?p=138 for discussion 
and links).
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First: HDOP (horizontal dilution of precision) is the quadratic mean of "EDOP" 
(easting DOP) and "NDOP" (northing DOP).
If we had both EDOP and NDOP, we could represent the DOP in JOSM as an ellipse 
instead of a circle (as in http://www.outdoormaps.org/?p=128).
Use case: You have two GPS tracks. On both, you went through Queen's road and 
King's road.
On Queen's Road, the two GPX tracks are 50 meters apart, one (track A) on the 
east, the other on the west (track B). Track B has both high EDOP and NDOP on 
all points. Track A has high NDOP but very low EDOP. So, for the purpose of 
mapping a road oriented north-south, track A is very good. You discard track B 
and map Queen's Road on top of track A.

On King's Road, the two GPX tracks are 50 meters apart, one (track A) on the 
east, the other on the west (track B). Both tracks A and B have high EDOP and 
NDOP on all points of King's road. You draw  King's Road in the middle, at an 
equal distance of tracks A and B. (In OpenStreetMap, you may add those tags: 
fixme=resurvey; note=averaged from 2 low-precision GPS tracks).

Editors like JOSM would show the DOP like an ellipse, not like a circle


I provide some working prototype code (in R) and alink to the maths on how to 
do this at http://www.outdoormaps.org/?p=138; nothing hard here, tell me if I 
can help.

(A further improvement would be actually to store the direction of the highest 
DOP: this may not always be north-south or east-west).

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Second: DOP conveys only the information on the position of the satellite. As 
discussed in the above link, SNR is equally important. One or more satellite(s) 
with a very low SNR may signal reflections or signal that is so low that it 
becomes barely usable.
Mean SNR (accross all used satellites) is probably an excellent start.
In particular according to one scientific reference[1], it is useful in 
combination to the number of satellites. 
[1] Pigott, "Inferring Transportation Mode using Smartphone Sensor Data", 2011, 
p. 42
http://www.piggott.me.uk/blog/2011/08/25/inferring-transportation-mode-using-sma
rtphone-sensor-data/

Ref [1] present a use case. ANother one would be to have circles/ellipse in 
JOSM that would show the accuracy based on combining xDOP and SNR.

What steps will reproduce the problem?
1. Set to start logging points
2. Set to email log every hour
3.

What is the expected output? What do you see instead?
I am getting the email every hour like supposed to. However, it is the same log 
file from the first hour being sent over and over again every hour. For 
example, if i sit at home for the first hour....then leave for a couple hours I 
keep getting the first hour log saying I was at home the whole time.

What version of the product are you using? On what operating system?
Not sure of version....just downloaded from the market so probably the newest 
version...on Android

Please provide any additional information below.

What steps will reproduce the problem?
1. Export KML File on french version of Android

What is the expected output? What do you see instead?
GPS coordonates should be formated xx.xxxxx but are written xx,xxxxx

What version of the product are you using? On what operating system?
French version of Android on HTC Dream

Please provide any additional information below.
The following code fixes the issue in GPSLoggerActivity.java at line 45
    private final Locale MyEngLocal = new Locale("ENGLISH");
    private final DecimalFormatSymbols MyDecimalSep = new 
DecimalFormatSymbols(MyEngLocal);
    private final DecimalFormat sevenSigDigits = new DecimalFormat
("0.#######",MyDecimalSep);

What steps will reproduce the problem?
1. Click the Start button in GPSLogger.
2. Click the phones Home button to display the desktop.
3. Click and drag open the notification area in the left corner.
4. Click on the GPSLoggerService

What is the expected output? What do you see instead?
The GPSLoggerActivity should be displayed but instead nothing happens.

What version of the product are you using? On what operating system?
Latest revision from SVN in emulator and Google Dev Phone 1.

The problem can be solved by changing one line in GPSLoggerService.java to
instead pass the GPSLoggerActivity class (see attached patch).

What steps will reproduce the problem?

  1. menu -> Annotate

  2. Enter something with an &

What is the expected output?

  ...<name>foo &amp; bar</name><desc>foo &amp; bar</desc>...

What do you see instead?

  ...<name>foo & bar</name><desc>foo & bar</desc>...

What version of the product are you using? On what operating system?

  v1.0.3
  Android 1.5 (HTC Hero customised for UK Orange)

Please provide any additional information below.

  I suspect this is a general problem with XML special chars, not just
ampersands. I know, I'm warned to use only letters and numbers in the
annotation dialog, but it's easy to forget and for mapping I need to be
able to make _verbatim_ records of what I see (signposts, for example).
Blaming the user is a Bad Thing :)

What steps will reproduce the problem?
1. Set it to send emails @ 8 hours (a 24hr option would be great too thanks)
2. Set it recording
3. Wait 8 hours (nothing happens)

What is the expected output? What do you see instead?
It should be sending the files consistently as per the time set, or if the 
phone is off, then once it is turned back on again. Instead I get an email once 
every few days. Then I can get two in one hour. Seems to be no pattern to it.

What version of the product are you using? On what operating system?
Latest version of GPS Logger. Android 2.1

Please provide any additional information below.
Tablet is ZTE V9 7" Tablet.

Thanks.
Warwick

What steps will reproduce the problem?
1. export a kml file in german android version
2.
3.

What is the expected output? What do you see instead?
coordinates should be in format xx.xxxxx instead they are xx,xxxxx

What version of the product are you using? On what operating system?
android 1.5, german version

Please provide any additional information below.

Dear friends,

I am postgraduate student in Hong Kong, doing research in mobile applications. 
I really like your project, as it is simple yet useful enough.

Recently, we are analyzing sensor data usage in Android applications using a 
research prototype. We found one interesting issue in your project.

If the GPS data is of low accuracy, then the sensed data will not be recorded 
into database. However, it is highly possible that GPS cannot provide accurate 
data in indoor area (especially in Hong Kong). So if users do not stop tracking 
when they are indoor, it is possible that much energy is spent, but the user 
only gets very limited data recorded in database. In some sense, much energy is 
wasted. I wonder whether there could be a better design. For example, when the 
app found that the data provided by GPS is not accurate for a long time (say 5 
mins), then the app unregisters the location listener and starts a timer which 
can re-register the location listener after a period (say 40 mins). Of course, 
we should let users know that the tracking is temporarily stopped because the 
GPS data is noisy.

We hope in this way, this great little app can be more energy efficient. We 
look forward to hearing from you. Thank you!