[aprssig] Tracking non-APRS mobiles by MileMark

[Robert Bruninga]

The APRS milemark database allows your program to 
quickly locate other Hams that are mobile and only
know their present location by milemark while traveling
the interstates.  Since APRS dead-reckons objects,
it is easy to put "joe" on the map on interstate XX at
milemark YY headed west for example.

He will continue to move that way so that for the
duration of your QSO or for when you are traveling 
to dayton and talking to all those folks on "52"
you can actually see them moving for hours.

I just updated the MILE-MARK file to include the
missing California, Pennsylvania and Maine interstates.
So the USA is now pretty much complete except for
MA which still does not use milemarks.

The MM-DATA.DAT file is used by APRSdos.
The original MILEMARK.DAT is still used by
UIview. and is also being updated this week
from my new data.

I hope all other APRS programs also show these milemarks
on their maps so that all APRS users can communicate 
with non-APRS users about their mobile locations on the
interstates.  Especially while driving to Dayton with 
everyone on the road.

To see how they look on APRSdos screen, see the
http://www.ew.usna.edu/~bruninga/aprs/aprsdos.html
page about 90% down the page.  There is a link there to
download the file.  It is a text file..  It overlays a 1 mile
circle over every 5, 10, or 20 mile mark depending on your
zoom level.  Very easy to estimate someone's position.

de Wb4APR, Bob