[aprssig] APRS System Overiding Fundamentals

Ray McKnight shortsheep at worldnet.att.net
Wed Mar 9 02:09:25 CST 2005

Well, please correct me if I'm wrong, but reading Rogers's help
File, he is very clear on this and makes a point to boldface, highlight
It, and even put it in a separate paragraph to emphasize it!

UI-View does NOT "DR" an object in a straight line!!
An object can be set to move along a course (which is a heading
And speed), and that movement will be determined - ***if you want
UI-View to do this for you automatically without intervention or
Manual updating*** - based upon the course and speed of the object
At the time it was created.  But here's the BIG CAVEAT - it follows
A GREAT CIRCLE ROUTE - therefore it NEVER EVER can actually go in
A "straight line".  A "straight line" is RHUMB LINE navigation, and
Is actually NOT the shortest distance between two points on a globe.
Using RHUMB LINE your heading will vary according to the angle of
Your course compared to the longitude lines, but using great circle
Your heading will ALWAYS remain the same as referenced to longitude
Until you reach your destination.

For short distances, the difference is almost immeasurable.
For longer distances, thousands of miles, it is blatantly obvious.
Nearer the poles it is also more defined.

Please, let's not confuse this!

I apologize for the lengthy reply which probably should be
Confined to the UI-View group.

-----Original Message-----
From: aprssig-bounces at lists.tapr.org [mailto:aprssig-bounces at lists.tapr.org]
On Behalf Of Jim Andrews
Sent: Tuesday, March 08, 2005 23:24
To: TAPR APRS Mailing List
Subject: RE: [aprssig] APRS System Overiding Fundamentals

>A couple of things off the top of my head:
>The ability to have an object follow a pre-defined route
>The ability to click on the map to create an object

Which is why I raised the question, because this is the functionality in
I've been using!

Click on the map where you want the object to be created and press F5,
can be set to follow a straight line.

Can an APRSdos-generated object follow a route via a number of preset


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