[aprssig] APRS data dump for a month or two

[apratt at bestbits.org]

> Sounds like a perfect job for the APRS World archive!
> http://archive.aprsworld.net/archive/

Close! But it looks like this only keeps one packet per source station
in each hour.

My goal is to map coverage in California and the West, especially in
remote and less-traveled areas. When only a small number of active
mobile stations ever pass through an area of interest, keeping just
one report per hour limits my chance of seeing the coverage.

By way of data reduction, I only need one report per square mile or
so. Rather than filtering out multiple reports from the same station,
I'd prefer to get all the reports from moving *stations* and remove
multiple reports from the same *position*. I can also exclude reports
outside my geographic area of interest.

Still with enough hours of data from the archive I can build a
statistical picture... Thanks!

-- Allan Pratt, apratt at bestbits.org