Coasting symbol not always displayed

[Bernardo Reis (1096507)]

For some reason, the coasting symbol is not always being displayed.

Symbol is correctly defined in the file and is show in the scope:

 

However, for some reason it's not always being displayed (mainly to aircraft flying westbound), showing no symbol at all:

Here, flying eastbound into Madrid, the symbol appears:

 

Any suggestions? Topsky version is 2.4.

Edited August 28, 2022 by Bernardo Reis (1096507)

[Juha Holopainen]

The plugin displays the coasting symbol when the track position has a greater than zero radar flag (i.e. any type of radar return) but the age of the latest radar return is greater than 15 seconds. No symbol at all is likely caused by the track position returning zero for the radar flag, but EuroScope drawing the label anyway. There's no real guidance available on when EuroScope stops displaying the label so I've just stopped displaying a radar position symbol immediately for all tracks that return zero for the radar flag (to avoid drawing position symbols without labels). For tracks reaching the limit of radar coverage, I've seen the symbol go from the radar symbol to coasting and then no symbol at all for a short period before the track turns into a FPASD track, but the no-symbol-at-all period has never been long enough to bother me enough to start spending a lot of time trying to improve it. If the tracks display no symbol at all for an extended period of time (several minutes), I could have a look at some point, but I'd need a log file that displays the behavior.

[Bernardo Reis (1096507)]

The track display remains without symbol for a couple of seconds, which is not long but it bothers me and makes it less evident that it left radar coverage.

What I just don't understand it's why it draws only to the East. Anyway, now that you talked about it, it's probably Euroscope drawing the symbol, and since we have no symbols defined as per Topsky manual, it doesn't show any symbol at all. What would be the disadvantages if we had the coasting symbol defined in Euroscope?

[Juha Holopainen]

Any symbols defined in EuroScope could not be controlled by the plugin. For example the coloring and display of the symbols would be decided by EuroScope so you might get a symbol drawn simultaneously by the plugin and EuroScope, and the EuroScope symbols would not respond to any plugin-based filtering. Given that the coasting symbol is usually short-lived, the disadvantages would be less visible than for the other symbols. Whether the advantages would outweigh the disadvantages, I can't say - very much dependent on the specific setup and situation.