[aprssig] Need some Coordinate and math help

[kb2scs at optonline.net]

Hi All
         I am presently working on a new mapping system that uses the 
USGS DLG 1000k optional format.

What I need is a mathematical formula to take the UTM coordinates in 
the DLG file and convert them to Lat and long.

I have searched the USGS site, I have exhausted Google.
Please help

Let us hope we never witness the "Silence Of The Hams"
73 DE John  KB2SCS
       E-Mail:            kb2scs at arrl.net
       APRS-SCS     http://www.tapr.org/~kb2scs
       Web Page:     http://www.qsl.net/kb2scs