Tuesday, January 22, 2008

Rotating APRS symbols

I've just installed the rotating APRS symbol code on the production server. I hope it won't slow your browsers down too much. It will cause some slowness, and eat a bit more memory, but it might be worth it.

The symbols have been rotated in 10° steps (0° to 350°) using Gimp's scripting language (Scheme / Script-Fu) and a little Perl. This was my first piece of Scheme, and my favorite quote from the Script-Fu tutorials was "Debugging Script-Fu scripts is only slightly less painful than stabbing yourself in the eye with a dull spoon". It's so true. I would have used imagemagick, but it broke the transparency. So I learned a new programming language. :)


Anonymous said...

it works VERY nice !

Anonymous said...


Anonymous said...

Very very good!

Would it be possible to use similar symbols as used by Shipplotter when feeding Goggle Earth on my PC? As far as I can see each ship is then shown in GE as a symbol reflecting both its SIZE as well as its orientation/heading? (once you get down below a certain level that is)

Best regards

Hessu said...

Technically speaking, yes. It requires a lot more symbol files to be generated on the server, and that's mostly manual work. Simply scaling the current icons up for bigger ships would make them very ugly, so I'd need to draw new longer icons for each longer version of each vessel class. Maybe some day, but not in the near future...

I should receive the new server this week, so I'll concentrate on getting that running, and making some sort of HA configuration on top of the two or three hosts.