[Qgis-developer] Proposal: Add Qwt as a soft dependency for GPS integration

[Marco Hugentobler]

Hi all

The non-gui part is in src/core/gps now. The code is experimental and I hope 
to receive a lot of improvements :-)

There is a base class QgsGPSConnection, subclassed by QgsNMEA connection. So 
it would also be possible to add support for non-NMEA connections by creating 
new subclasses. QgsGPSConnection emits a signal (stateChanged) that contains 
the last received data.
To query the gps connection in the background, there is the class  
QgsGPSTrackerThread.

The code uses QExtSerial to access the serial port platform independently. 
Currently, there is no support for USB devices. This could be implemented as a 
new subclass of QIODevice.

Tim and I tested it successfully with our Garmin eTrex H devices, using an 
usb-serial adapter cable.  

To parse the individual nmea sentences, code from libnmea is used. The code is 
directly included in the qgis sources, so no other hard requirement ;-) . From 
what I see, it handles only the most important sentences, so there is also 
space for further extensions here.

Looking forward for your comments, suggestions, improvements.

Regards,
Marco

Am Mittwoch, 6. Januar 2010 11.00:35 schrieb Tim Sutton:
> Hi All
> 
> Marco and I have been working on C++ based GPS integration into QGIS
> core. The work has been sponsored by Navigo (http://www.gonavigo.ca/).
> 
> There are two parts:
> 
> - a gps background process that communicates with a GPS and extracts
> nmea strings and then propogates them to any listing classes
> - a user interface, implemented as a dock panel that shows position,
> signal strength bar chart, satellite polar chart, options
> 
> Similarly to Martin's gps project, the gps ui can be used to capture
> features (and attributes using the normal attribute dialog mechanism).
> The ui part uses Qwt for the charting functions. I would like to
> propose that we add Qwt5 as a soft dependency. If it is not present,
> the GPS ui parts will not be built (the background process part will
> still be built. Could you please let us know if you are happy for the
> inclusion of this soft dependency - and the GPS code itself?
> 
> If on, the other hand, people are inclined to make Qwt a hard
> dependency, that would be good to because I can then replace the
> raster props dialog histogram with a better charting implementation.
> 
> Regards
> 
> Tim
> 

-- 
Dr. Marco Hugentobler
HUGIS - GIS programming and consulting
Webereistrasse 66
CH-8134 Adliswil
marco at hugis.net
http://homepage.hispeed.ch/hugis
Technical Advisor QGIS Project Steering Committee