





SPECPR Users' Manual                                            Page 8-f22.1


_F_2_2: _G_r_a_p_h _D_i_g_i_t_i_z_a_t_i_o_n _u_s_i_n_g _a _T_a_b_l_e_t                     _A_l_i_a_s: _d_i_g_i[_t_i_z_e]

     This routine is a graphics digitization program.  _N_o_t_e: _t_h_i_s _r_o_u_t_i_n_e _i_s
_d_e_v_i_c_e-_s_p_e_c_i_f_i_c  _a_n_d  _m_u_s_t  _b_e _t_a_i_l_o_r_e_d _s_p_e_c_i_f_i_c_a_l_l_y _f_o_r _y_o_u_r _s_i_t_e; _s_e_e _y_o_u_r
_s_y_s_t_e_m _a_d_m_i_n_i_s_t_r_a_t_o_r _f_o_r _d_e_t_a_i_l_s).

     This program asks the user to define a graph by  digitizing  the  graph
limits.   Then  it accepts points from the tablet that are within the limits
of the graph and converts the x and y values into data values as defined  by
the  graph.   If  a  digitized point is outside the bounds of the graph, the
program will say so and ask if you want to redo the point, begin over, write
the data or exit.

     When you are finished digitizing, the program will prompt you  for  the
file  id  (v,  w,  d, u, or y).  The file must have positive protection set.
The program will first write the x data values and than the y values in  the
following record.  The protection is updated as appropriate.

     To run f22, type

              _f_2_2

from math operations.  The program will return with the title page of f22.

Press return to continue.

     Digitize the upper left bound of the graph, lower left bound  (origin),
and  the  lower  right bound of the graph.  The program will return with the
values of the points in tablet coordinates, the amount that the  points  are
off  perpendicular, and the angle between the two axes.  If these values are
acceptable type "yes".

     The program will rotate the axis should it be not  exactly  perpendicu-
lar.   Then  you must enter the values of the digitized points starting with
the upper left, origin, lower right points.  Then you must enter the  limits
of the horizontal axis and the limits of the vertical axis of your graph.

     When the above is finished the program will return with  "ENTER  POINTS
FROM TABLET".  Now you can digitize points from your graph.

     If you somehow enter a point that is outside the limits of your  graph,
the  program  will  return  with  "POINT  OUT  OF BOUNDS".  You have various
options at this point.  Type

              r   to reenter the point.
                  This will not affect the data count.

              b   to begin entering the points again.
                  This allows you to start over without
                  having to reenter the limits etc.






              w   when finished entering points. This
                  will put you in the writing mode to
                  write your data to a file.

              x   will exit you from the program.


     If you are finished entering points from the tablet, and wish to  write
the  data, digitize a point outside the graph.  The program will return with
"POINT OUT OF BOUNDS".  Type a

              _w

to write the data.

     To write the data, the program will prompt you to enter the file id  of
the  file and record number where you want the data to be written.  Then you
are prompted to type in the title of the data set that will  contain  the  x
(horizontal) values, then after that the title of the data set that contains
the y (vertical) values. The data are then written.

     After all that you will be asked if you want to digitize another graph.
Answer yes or no, if no then the program exits.


































