.noprint
.erase
.f77 final = .false.
xax 0,200
yax -7.5,-5.5
xlabel X = (R+z)/H Scaled Planetary Radius, Altitude, and Scale Height

.f77 msg1 = char(128+ichar('/'))//'10'//char(128+ichar('\'))
.f77 msg2 = char(128+ichar('['))//'x'//char(128+ichar(']'))
.f77 msg = 'max('//msg2//'=0,90) log'//msg1//'( Relative Error )'
ylabel $msg

.f77 msg = 'Worst-Case Accuracy of Chapman Function Approximations vs X'
.f77 if(final)msg=' '
title $msg

.f77 col = 3
.f77 sym = 0
.gosub draw1
.f77 col = 5
.gosub draw1
.f77 col = 7
.gosub draw1

.f77 col = 9
.f77 sym = 1001
.gosub draw1

set text user
set text left

.f77 msg = '(a) Present Differential Equation'
.f77 if(final)msg='(a)'
text 80,-6.1,0,0,0,$msg

.f77 msg = '(b) Ch31b Eqn 22 & 38'
.f77 if(final)msg='(b)'
text 80,-6.6,0,0,0,$msg

.f77 msg = '(c) Present Asymptotic'
.f77 if(final)msg='(c)'
text 80,-6.95,0,0,0,$msg

.f77 msg = '(d) Present Numerical real*4'
.f77 if(final)msg='(d)'
text 20,-7.18,0,0,0,$msg

gra end
.end

.label draw1
  col 1,$col
  inp chapacc.out
  .f77 ydata = alog10(ydata)
  gr nop/$sym