.noprint
.erase
.f77 final = .false.

lines /2
xax 0,90
yax -11,-1
set graph interval 9,10
.f77 msg = char(128+ichar('['))//'x'//char(128+ichar(']'))
.f77 msg = 'Solar Zenith Angle '//msg//' (degrees)'
xlabel $msg
.f77 msg = char(128+ichar('/'))//'10'//char(128+ichar('\'))
.f77 msg = 'Log'//msg//'( Relative Error )'
ylabel $msg
.f77 msg = 'Accuracy of Chapman Function Approximations vs'
.f77 msg = msg//' Solar Zenith Angle for X = 800'
.f77 if(final)msg=' '
title $msg

.f77 col = 2
.f77 sym = 0
.gosub draw1
.f77 col = 3
.gosub draw1
.f77 col = 4
.gosub draw1
.f77 col = 5
.f77 sym = 4
.gosub draw1

.f77 col = 6
.f77 sym = 1001
.gosub draw1
.f77 col = 7
.gosub draw1
.f77 col = 8
.gosub draw1

.f77 col = 9
.f77 sym = 2002
.gosub draw1
.f77 col = 10
.gosub draw1
.f77 col = 11
.gosub draw1

set text user

.f77 msg = '(a) GLG64 Eqn 11'
.f77 if(final)msg='(a)'
text 45,-1.7,0,0,0,$msg

.f77 msg = '(b) Fi64 Eqn 3'
.f77 if(final)msg='(b)'
text 10,-2.7,0,0,0,$msg

.f77 msg = '(c) Present Asymptotic, 1 term'
.f77 if(final)msg='(c)'
text 28,-3.45,0,0,0,$msg

.f77 msg = '(d) Sw64 Eqn 52'
.f77 if(final)msg='(d)'
text 55,-4.0,0,0,0,$msg

set text right
.f77 msg = '(e) Ch31b Eqn 38, 1 term'
.f77 if(final)msg='(e)'
text 70,-5.0,0,0,0,$msg

set text left
.f77 msg = '(f) Present Differential Equation'
.f77 if(final)msg='(f)'
text 20,-6.7,0,0,0,$msg

.f77 msg = '(g) Present Numerical real*4'
.f77 if(final)msg='(g)'
text  5,-9.0,0,0,0,$msg

.f77 msg = '(h) Ch31b'
.f77 if(final)msg='(h)'
text 51,-9.0,0,0,0,$msg
.f77 msg = 'Eqn 38'
.f77 if(final)msg=' '
text 51,-9.4,0,0,0,$msg

set text right
.f77 msg = '(i) Present Asymptotic'
.f77 if(final)msg='(i)'
text 43,-10.3,0,0,0,$msg

set text left
.f77 msg = '(j) Ch31b Eqn 22'
.f77 if(final)msg='(j)'
text 62,-10.3,0,0,0,$msg

gra end
.end

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