[FOSS-GPS] foxtrotgps: Tracking weather probes in addition to the own position

[Tilman Glötzner]

Dear all

I would like to use foxtrotgps to track the position of an extra object,
a weather probe, in addition to the own gps position.

So I have given it a try  and stored a proof of concept in
https://code.launchpad.net/~tilman1/foxtrotgps/foxtrotgps

What does it do?

The weather probes sent out their gps positions once a second. Their
signal can be decoded using RS (https://git?hub.com/rs1729/RS). The
output is a text datagram that contains among other things the current
gps postion

I added a thread that opens a port at 60050, and waits for datagram of
the RS program. Once it receive a datagram, it parses it, and draws the
position on the map -- thereby redrawing everything. This is all in the
files rs_functions.h and rs_functions.c that I added.

Questions:
- I know that the approach that I have implemented is not really
generic. Are there better approaches in how to extend foxtrotgps ?

- Once a GPS position is received, it is drawn. If a datagram from a
weather probe is received, everything i.e. the map window is redrawn. So
if a valid gps position is received and a datagram of the probe is
received, redrawing takes place twice per second. I wonder if it is
possible to only locally draw the probe position rather than redrawoing
everything.

Comments are appreciated.

Many thanks
Tilman