anchor.diff:                    read(tag,'(BN,F10.0)') incr
                     if (auto.eq.2.or.auto.eq.3) incr = -incr
                 endif
  +          elseif (tag(1:10).eq.'-empirical') then
  +              i = i + 1
  +              call getarg(i,emprel)
             elseif (tag(1:4).eq.'-gmt') then
                 kgmt = 1
                 i = i + 1
  
positive.code: C----
        IMPLICIT NONE
        CHARACTER*40 ffmf,fltf,magf,haff,staf,trgf,dspf,stnf,stsf,norf,
       1             shrf,coulf,gmtf
        INTEGER flttyp,auto,xy,prog,long
        REAL*8 incr,adist
        INTEGER nflt,FMAX
  
negative.code:       shrf = 'none'
        coulf = 'none'
        gmtf = 'none'
        emprel = 'WC'
        flttyp = 1
        auto = 0
        xy = 0
  