anchor.diff:        endif
   
         goto 1000
  -  991 call errmes('!! Error: problem with reading input (lon1 lat1 '//
  +  991 write(0,*) 'Offending line: ',trim(iline)
  +      call errmes('!! Error: problem with reading input (lon1 lat1 '//
        1                                                     'lon2 lat2)')
    8889 format(2F20.8)
    9999 format(2F20.8)
  
positive.code:               endif
                open (unit=12,file=ofile,status='unknown')
            endif
    101     read (input,*,err=991,end=102) lon1,lat1,lon2,lat2
                if (debug) then
                    write(0,*) 'Read line: ',lon1,lat1,lon2,lat2
                endif
                if (dabs(lat1).gt.90.0d0.or.dabs(lat2).gt.90.0d0) then
                    call errmes('!! Error: latitude is greater than 90')
                endif
                call ddistaz(dist,az,lon1,lat1,lon2,lat2)
  
negative.code:       PARAMETER (pi=4.0d0*datan(1.0d0),r2d=1.8d2/pi,radius=6371.0d0)
        REAL*8 lon1,lat1,lon2,lat2,dist,az,cmdin(4)
        CHARACTER*30 ifile,ofile
        CHARACTER*256 iline
        INTEGER c,p,input,i
        LOGICAL ex,debug
  
  