[aprssig] APRS Symbols- Direction/Vectoring

Spider spider at rivcom.net
Tue Dec 7 12:15:04 CST 2004

----- Original Message ----- 
From: "Steve Dimse" <k4hg at tapr.org>
To: "TAPR APRS Mailing List" <aprssig at lists.tapr.org>
Sent: Tuesday, December 07, 2004 10:31 AM
Subject: Re: [aprssig] APRS Symbols- Direction/Vectoring

On 12/7/04 at 8:22 AM Curt, WE7U <archer at eskimo.com> sent:

>Xastir has four rotations for each symbol.  We do flip pixels.
The problems I see with this are first, it only gives you 4 compass points,
second, it gives no indication of speed...so one of the 4 projections must 
used as well when a station is not moving, and finally, some icons are 
about the vertical axis, for example the balloon, so these can only show two
values (east/west/stationary) and (north/south).

I much prefer the way MacAPRS has done it for the last 10 years, a vector 
from the icon in the direction of travel, the length of the vector giving an
indication of speed. I need to work on this a bit, the red vectors can get 
lost on maps using red for


Maybe I'll let the user specify a color. This is experimental, comments

Steve K4HG

UI-View's speed sticks (okay, vectors) represent speed and direction.  For 
my map, I doubled the vector length so that I could see weather circulation 
across the country.  Works great!

Red vectors also conflict with Red NWS warnings....so being able to set the 
color of the vector is a nice touch.


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