Maidenhead is a grid system used by amateur radio operators. I crudely implemented a Maidenhead grid to longitude/latitude calculator, not limited to the 6 characters as often seen with other programs. Written in newbie python here on debian GNU/Linux. Download: lonlat2maiden, maiden2lonlat. See my notes, and Rene Kanters' 2004 augmentations.
First, in case you use DMS notation, convert it into decimal degrees,
$ set 120d51\'57.74\"E 24d10\'54.14\"N $ echo $1 $2 120d51'57.74"E 24d10'54.14"N $ set $(echo $1 $2|cs2cs +proj=latlong -f %.8f) $ echo $1 $2 120.86603889 24.18170556
Now we are ready to go,
$ echo $1 $2|lonlat2maiden PL04KE $ echo $1 $2|lonlat2maiden 22 #arbitrarily picking 22 PL04KE33WO16WF07TP38UR $ echo $1 $2|lonlat2maiden 22|maiden2lonlat 120.86603889 24.18170556 $ echo $1 $2|lonlat2maiden 22|maiden2lonlat|cs2cs +proj=latlong 120d51'57.74"E 24d10'54.14"N 0.000
By the way, as to just how many digits one needs for what granularity, we examine what the smallest length one can distinguish with the latitude parameter as we increase string length:
Len meters example 2 1111200.0000 PL 4 111120.0000 PL04 6 4630.0000 PL04KE 8 463.0000 PL04KE33 10 19.2917 PL04KE33WO 12 1.9292 PL04KE33WO16 14 0.0804 PL04KE33WO16WE 16 0.0080 PL04KE33WO16WE57 18 0.0003 PL04KE33WO16WE57NA
So, to dazzle your friends with millimeter precision, one need not make one's vanity Maidenhead locator too long after all. (Code used to make above output)
Hmmm, the Maidenhead system is sort of like Taiwan Power Company grids.
Last modified: 2007-09-14 01:10:18 +0800