Order Tray | Contact Us | Home | SIG Lists

[aprssig] Object Ownership and Replacement

Bob Bruninga bruninga at usna.edu
Sat Feb 9 18:23:26 UTC 2008


> Question...is it possible for someone to
> have "administrative rights" to delete/modify 
> someone else's objects?  If "yes", is there 
> a way to keep two administrators from battling 
> each other? 

Anyone can replace someone elses object at any time. That was fundamental to the design of APRS.  The most recent station with information about a "thing" could update where the "thing" is located without wasting a lot more packets in exchanging authorities.

All it takes is for station B to uplink an object with the same name as the original station A object, and transmit it.  Everyone will see the new object from B, and the original originating software (station A) will see that its object has been replaced and will STOP transmitting his old one.

That is why the original APRS clearly shows these objects in two distinct colors.  YELLOW objects are your own that you are transmtting.  Violet ones are eveyrone elses.  As soon as anyone else takes over your object, then your YELLOW object turns violet so that you can always see at a glance if you are in control or not.

But alas, this fundamental color distinction to give high-visibility to object ownership is just another one of those little things left out of most follow on clients, undermining the integrity of the APRS situational display...

Oh well...

P.S.  The object must have the exact identical case-sensitive spelling to be replaced (only FINDU ignores case).  And if the original station for some reason does not hear the replacement object from B he first time, and so A resends his, then B's might get canceled.  So again, this is why is is imperative to see the OWNERSHIP COLORS right on the object so you can make sure that your object is active from your station and has not been usurped by someone else.

In any case, the owner's call is associated with any object to eliminate any ambiguity.

Bob, WB4APR




More information about the aprssig mailing list