Chico #6185

For the magnetic file:
Offset was removed from line 725.  Tie line 4051 had negative values in part of totmag.  
These were brought into conformity by subtracting them from 65537. 
Tie lines 4041 through 4081 had erroneous data in resmag.  The resmag was recalculated 
for these lines using IGRF75, 09/01/80 as the date, and the elevation was determined by 
sampling a topo grid and adding those values to the radaralt.  The resmag for these tie 
lines will need further adjusting if used.
Records were removed where there was no totmag and resmag.

In the radiometric file, the resmag was not corrected at all.