Re: [Gpsbabel-misc] Mac GPSBabel and Live NMEA

[Robert L. <rob...@us...>]

ZapWizard wrote:

>    I have a NMEA USB GPS Puck and I want to use Google Earth for
>    GPS on my Mac Mini; OS X 1.4.3 I downloaded GPSBabel 1.2.5 for
>    OS X, but discovered that it only does live Garmin and Magellan
>    conversion. Is this a feature that was simply not included with
>    the build, or does GPSBabel not do NMEA live conversion at all? Is

GPSBabel doesn't claim to do realtime NMEA at all. It is something I've
considered adding from time to time, but it's not really very high on
my list as it doesn't really fit our mission statement. (See the first
sentence on www.gpsbabel.org) Positioning info is sort of like track
data, but not.



[ Warning: Stupid GPSBabel Trick Follows ] 

One thing you can do, if you want this badly enough, is script GPSBabel
to read the device at some interval, write a KML file, and then use
GE's network refresh to update your position. So run a script that's
something like:

	while :
	do
	   gpsbabel -i garmin,get_posn -f usb: -o kml -F /tmp/blah.kml
	   sleep 2
	done

and then point GE to net refresh blah.kml every few seconds.

If this thing is really NMEA (adjust device name to suit) 

        while :
        do
           head -20 /dev/ttyACM0 | gpsbabel -i nmea -f -  -o kml -F /tmp/blah.kml
#           sleep 2
        done

Adjust the number of lines read to ensure that you get at least one full
"paragraph" of NMEA sentences - two would be better. On most devices,
there's enough redundancy, though, that even as you drift within the
paragraph since all you want is a lat/lon pair you'll probably find
you're never more than ten sentences from being able to grab onto them
as they come by. You'll get some crazy stuff if GPSbabel truncates the
file while GE is reading it. Bonus geek points could be earned for
modifying the above to write to a named pipe or fifo.

Honestly, neither GPSBabel nor GE are particularly well suited for
moving map info.

RJL