[Qgis-developer] Accessing GPS devices platform independently

[Martin Dobias]

On Mon, Nov 9, 2009 at 3:21 PM, Martin Weis
<martin.weis.newsadress at gmx.de> wrote:
>>> On 2009-09-05, at 7:34, Marco Hugentobler <marco at hugis.net> wrote:
>>>> I see there are some projects connecting gps devices and QGIS
>>>> (QGIS track GPS, Quantum Navigator, QGIS mapper).
>
> I did not understand how to use it, maybe someone can guide me how to
> install/test the plugin/navigator (Navigator seems not to compile
> against recent QGIS versions)? This might be a good basis :-)

Right Quantu Navigator app used to work only with old versions of QGIS
and currently I'm not planning to do any updates to it. But it
features only a gps emulator, no tracking from a real device.
QGIS mapper has its gps backend written in python, so that would mean
porting it to c++ (shouldn't be a big deal).
Never tried trackgps plugin, but AFAIK it uses the code from qgis mapper.

>>>> Is there already some NMEA related code?
>
> Just tried to write some code for myself (another project), but then
> I had a look into http://nmea.sourceforge.net/, which seems to be a
> useful library for this task. So far I only looked at the code and did
> not use it. The gpsd implementation is also very sophisticated, at least
> the parser is worth looking at. And there is gpsbabel, which might be
> handy here.
> Platform independent access to serial ports may be implemented using
> http://code.google.com/p/qextserialport/ , although the implementation
> seems to be a bit crude (doubled code/Classes for win/posix systems).
> Got that running (on linux) already...

NMEA parsing is relatively simple so instead of using some external
library in C it might be better to write one C++ class that would do
it... Regarding serial port communication, I've used QextSerialPort by
myself and seems to be a good choice.


>> Am Samstag, 5. September 2009 15.26:00 schrieb bob @ SHAW:
>>> Hi Marco: A few months ago I started work on a GPS plugin that
>>> would work on Windows since gpsd doesn't work there. I used Martin
>
> Maybe you can achieve gpsd-similar results under WIN using
> http://gpsfeed.sourceforge.net/ , which is a small tcl program that
> listens to a serial port and provides the nmea data over a given port,
> just like gpsd does with:
> http://localhost:2947/?r

My idea is that we should support NMEA input generically on all
platforms, additionally with gpsd support to enable use with some
devices that don't send NMEA. Never tried gpsfeed so not sure what the
results would be...


> Maybe I could help with this sooner or later, but first I need to get a
> dev system properly set up and read all the dev-infos in the wiki.
> Please contact me, if you have suggestions, how I could help.

I think the result from hackfest was that we surely want real time GPS
tracking functionality in core library, but I don't remember anyone
volunteering to implement it. So we would be very happy to see any
patch that adds this feature.

Regards
Martin