





SPECPR Users' Manual                                            Page 8-f16.1


_F_1_6:  _L_i_n_e _S_e_g_m_e_n_t _D_a_t_a _G_e_n_e_r_a_t_o_r                           _A_l_i_a_s: _l_i_n_e[_g_e_n]

     This routine generates arrays of data by  linearly  interpolating  user
(x,y)  pairs to a wavelength set.  Given data values at specific wavelengths
or channels typed in by  the  user,  this  routine  computes  line  segments
between the points the user has input.

     Upon entering the routine, the user has  the  option  of  changing  the
current  wavelength set in use by typing the file ID letter (upper case) and
the record number, or assigning the channel numbers as  "wavelength  values"
with  the  maximum number of channels given by the wavelength record.  To do
this, type h and the wavelength record number to assign channel numbers with
the number of channels given by the wavelength record number.  Examples:

        V23      Assign wavelength data set in v23.
        h482     Assign the array value = the wavelength data value.
                 (channel 1 = 1.0, channel 2 = 2.0, ... channel 482 = 482.0).
        C482     same as h482, but the wavelength routines assign the
                 wavelength set before it is handed to the f16 routine.
        <return> Use existing wavelength set in use.


     After this initialization, the routine repeatedly asks  for  the  first
two  data  values--the  (x,y)  coordinates for user point #1, then #2, etc.,
until you are through.  Enter the data values separated by a space.  At each
command point, a number of control options can be entered:

e or x   will cause the routine to exit.

rn       return to step n, where n is the  step  number.   This  allows  the
         return  to  any  previous input step so it may be changed (and then
         you may return to the last step before you went to step  n).   Note
         that  you  cannot change an x value (wavelength) to a value greater
         than that in the next step--to do that, you must delete the follow-
         ing steps.

dn       delete steps.  Using  this  command,  all  data  values  after  and
         including  step  n  will be deleted; command control returns to the
         first step deleted.

ln       is a list command which will  list  up  to  25  entries  previously
         entered  with  the  step  number.   Here (n) is optional.  If it is
         used, the routine lists from step number n to step n+24.

b        for begin analysis.  The routine calculates all data values in  the
         array between each set of ordered pairs.


     No input spectrum is  required  because  you  are  creating  data,  not
operating  on  data.   If  an  input  file  was  called, an error message is
printed, and the routine will hard exit.





     All operations are checked for validity.  If a given operation produces
an  error,  a  message  will  be  printed  stating what caused the error and
whether or not the routine can continue.  If it can, the routine asks  again
for the data.  If not, the routine will exit, hard or soft, depending on the
severity of the condition.  Note that all x data values  (e.g.  wavelengths)
must be in increasing order, or error messages will result.



















































