subroutine resltnr (idms,ndiv)
c
c this routine determines the plot resoltion ndiv
c the plot resolution varies from 60 to 180 scan lines
c  written by j.l.green jan 27 1982
c  updated jfe johnson 11 feb 82
c
c returns following ndivs for idms (ms) in following ranges
c    idms lt 30 minutes   ndiv=60
c    idms lt 60 minutes   ndiv=120
c    idms ge 60 minutes   ndiv=180
c
c----------------------------------------------------------------------|
c                                                                      |
c      modified by     r.l.west     intergraph      4-dec-1984         |
c               modified to allow user to change the default ndiv      |
c                                                                      |
c----------------------------------------------------------------------|
c
      integer*4 ndiv
      real*8    idms,rmins
      data      ntm/0/
c
      rmins=idms/60000000.0d0
c
c the resolution is similar to the time span of the plot
c in minutes
c
      if (ntm .eq. 0) then
         ndiv=60
         if (rmins .ge. 30.0d0) ndiv=120
         if (rmins .ge. 60.0d0) ndiv=180
c         call iask (ndiv,'standard default')
         write (*, 50), ndiv
   50    format ('Enter time resolution divisions (recommend = ',
     *            i3, '): ', $)
         read (*,*) ndiv
         ntm=1
      end if
c
      return
      end