#
# do_grid.pro
#
# Usage: call do_grid
#
# execute an nxm grid with offsets size1 (E-W) and size2 (N-S). Take a picture 
# at each position and return to the starting position when done. The grid 
# begins in the SW corner and procedes in successive rows, ending in the NE 
# corner. This script is patterned after the wfire tcl script do_grid.
#
# RDB. 15 Feb 99
#
	
        yorn 'Disable the Tip Tilt guider during offsets'
        if (yorn==1)
          usetip=1
        else
          usetip=2
        end_if

	ask 'Enter number of positions to take in E/W direction: ' ewnum
	ask 'Enter number of positions to take in N/S direction: ' nsnum
	ask 'What is the E/W separation between pictures in arcsec?' size1
	ask 'What is the N/S separation between pictures in arcsec?' size2

        call askpars
	
	totpics=ewnum*nsnum

	printf 'Positions: E/W  = %i6' ewnum
	printf '           N/S  = %i6' nsnum
 	printf 'Separations     = %f7.1 %f7.1 arcsec' size1 size2
	printf 'Total Positions = %i6' totpics

	if (totpics>100)
	  alert 'I hope you know what you are doing!' 2 1
        end_if

	yorn 'Are the OBSERVE params OK and TELESCOPE centered'

        if (yorn~=1)
	  printf 'Aborting sequence: reset parameters/center telescope'
	  printf 'and try again'
	  return
        end_if
 
	iew=((ewnum-1)/2.0)*(-size1)
	ins=((nsnum-1)/2.0)*(-size2)

	if (usetip==1)
	  call ttd
	end_if
	offset ra=iew dec=ins twait=0
	if (usetip==1)
	  call tte
	end_if

        do i=1,nsnum
	  do j=1,ewnum 
	    avego $coad
            if (j<ewnum) 
	      if (usetip==1)
                call ttd
              end_if
	      offset ra=size1 dec=0.0 twait=0
	      if (usetip==1)
	        call tte
	      end_if
            end_if
	  end_do
          if (i<nsnum)
	    if (usetip==1)
              call ttd
	    end_if
	    offset ra=2*iew dec=size2 twait=0
	    if (usetip==1)
              call tte
	    end_if
          end_if
	end_do

	if (usetip==1)
	  call ttd
	end_if
	offset ra=iew dec=ins twait=0
	if (usetip==1)
          call tte
	end_if

	alert 'GRID COMPLETED' 3 1
end