From: alan curry <acurry@au...> - 2002-12-07 01:25:21
Today while I was out caching, I noticed that my waypoints in my yellow
Etrex were slightly off. I had downloaded them with the following
gpsbabel -i geo -f trad.loc -o garmin -F /dev/ttyS0
trad.loc contained this entry:
<name id="GC9B2C"><![CDATA[FORE THE TRAIL by BESSFAM]]></name>
<coord lat="30.7059" lon="-97.7190166666667"/>
<link text="Cache Details"
After downloading, my Etrex showed:
Downloading with EasyGPS showed:
Is libjeeps incorrect or should I not be concerned with the difference?
From: Robert Lipe <robertlipe@us...> - 2002-12-09 04:14:45
alan curry wrote:
> Is libjeeps incorrect or should I not be concerned with the difference?
Various floating point rounding errors have haunted the industry for
a long time so I can't say I'm shocked to hear this. If you want to
track it down, start looking at GPS_Dxxx_Send and really scrutinize that
GPS_Math_Deg_to_Semi stuff. After all, you need less than 8 significant
digits in in this so it isn't like we're exactly pushing the bounds of
math or anything.
That said, I think the difference is beyond the precision of
consumer-grade GPS anyway, isn't it?