[aprssig] APRS activity area animation

[Heikki Hannikainen]

   Inspired by the APRS activity map by Lynn, KJ4ERJ, I've produced some 
APRS activity plots over longer time frames. These animations cover mobile 
APRS traffic from March 2008 to the end of February 2009:

   http://aprs.fi/doc/stats/APRS-traffic-density-US-200803-200902.gif
   http://aprs.fi/doc/stats/APRS-traffic-density-EU-N-200803-200902.gif

   Only moving stations are shown here, and i've made an attempt to remove 
all internet-only stations (based on TCP* paths and the q construct). I 
haven't removed airplanes, balloons or satellites yet, though.

   The map shows areas with even a little APRS activity with a red colour, 
so a single airplane flight is visible as a thin red line. Currently the 
colour scaling and palette is not really tuned for communicating the 
relative amount of APRS activity, just the presence of any activity.

   Also, it doesn't really work as a coverage diagram, because the 
plotting algorithm doesn't try to estimate any additional areas which 
might be covered besides the points which were transmitted by trackers, 
but it does give you *some* idea where APRS network coverage might exist.

   Larger cities are marked with blue circles.

   The plots are produced in PostScript vector format and then converted to 
raster images and animations. If someone would like to publish these in a 
magazine or something, I can provide customized PostScript plots over 
specific areas or timeframes.

   The data comes from the http://aprs.fi/ backend database, which 
currently covers 12 months of history. I intend to develop the scripts to 
do plots like this automatically for all APRS active countries and states. 
Would someone happen to have the dimension coordinates for all the US 
states (min/max latitude/longitude values which contain the whole state)?

   - Hessu, OH7LZB (http://aprs.fi/)