GPS logger / field data collection

Jim Morris ml at
Mon Aug 18 23:00:06 CEST 2008

Hi Brian,

I like this idea, I just added gpsd to my Qtopia build, and added some simple
code to my Qtopia based sunset calculator I wrote eons ago for my Zaurus, the GPS part
simply gets current lat and long to calculate sunset/sunrise at your current location.
Previously I had a city selector for that.

I also wanted a pedometer, and I like the idea of a data logger, because I can post process the data 
with numerous things.

I was kind of surprised that gpsd didn't give me a simple way to just get the current location, I 
had to capture 5 sentences to do that simple thing, but what I really wanted was to simply get the 
last known lat and long I was at. With the data logger I can presumably do that by getting the last 
entry of the log.

I think the first thing to answer is the log format, any progress on defining that?

I'll work on code to extract the log info for a simple pedometer, also if you can define the log 
format I may be able to write an initial logger.

I think the logger needs to be platform independent as I will be writing all my code for Qtopia, but 
obviously we have 3 of 4 platforms to deal with, and only the graphical part will be different. 
(GTK/X vs QT/FB).

I also write in Ruby whenever possible, so we probably need a library that can read the log format 
from c/c++/python/ruby etc. (XML would be able to do that but I agree probably too verbose, how 
about tokenized XML?)

BTW my pedometer should be able to tell me the average , max & min speed I walked, and the total 
time and distance pretty simple stuff.

Brian Wilson wrote:
> One of the main reasons I got my Freerunner was to play with its GPS
> features. I want to be able to use it as a replacement for
> closed-source applications like TDS Solo Field and ESRI ArcPad.
> Especially I want something that would facilitate my volunteer
> "citizen scientist" work
> At the rate I am going I will probably never have more than 15 minutes
> a day to work towards this.
> In spite of this I decided to spell out what I have been thinking
> about in a wiki page because it would take too much space here and I
> think the interest might not be high enough to clutter up this very
> busy list with yet another very involved topic.
> I have a GPS in my pocket most of the time. I use a Garmin on my
> bicycles and on hikes. I have used various TDS and Trimble and ESRI
> products. Being a software developer I want something that I can tweak
> and tune and none of these commercial products even comes close to
> what I have in mind.
> Therefore I started this page:
> to talk about it
> and the intro there says this:
> --
> This page was created to address the use cases mentioned in GTA02 GPS, including
>     * I want to log GPS data for later analysis.
>     * I want to collect GPS data for scientific field work (forestry,
> biology, etc)
> The page was started on 17 August 2008 mostly as a thought exercise.
> Please jump in and add to it.
> Cheers,
> Brian Wilson
> Corvallis Oregon
> _______________________________________________
> Openmoko community mailing list
> community at

Jim Morris,

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