[aprssig] AVRS/APRS-Alert Updates

John Gorkos jgorkos at gmail.com
Tue Oct 4 09:18:51 EDT 2011


I'm probably just using the wrong order in bearings.  I keep showing up E of 
Sugar Hill, when I'm really west.  I'll fix that.


On Friday, September 30, 2011 05:15:03 PM Lynn W. Deffenbaugh wrote:
> And I learned the hard way that reversing the bearing isn't a matter of
> swapping it 180 degrees.  That'll look close to right for some spots on
> the globe but be frantically off for other pairs of coordinates.  You
> have to reverse the arguments to your Haversine calculation (or whatever
> you're doing) to get the proper bearing relative to the other side.
> 
> Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32
> 
> On 9/30/2011 4:56 PM, Keith VE7GDH wrote:
> > I just tried this, but for the callsign I entered, it showed 68 km
> > south of
> > Vancouver BC instead of 68 km north of Vancouver. Ah... km. Does it
> > perhaps use km north of 49N and miles for sout of 49N? I'm south of
> > 49N, but most definitely in Canada.
> > 
> > Another example... I entered the digi THYNNE and it returned information
> > that it was 95.24 km WSW of Chilliwack. In fact, it is NE of Chilliwack
> > by about that distance. It seems to be providing the reversed direction.
> > Not a huge problem when someone knows the geography, but it could
> > be confusing for a visitor.
> > 
> > Try sending LOCATE VE7GDH to AVRS and it will return 18 km west
> > of Duncan. I am most definitely east of Duncan.
> > 
> > 73 es cul - Keith VE7GDH
> > 
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