Different versions
==================

I have been tracking the COVID-19  cases development in my country. I'm
trying  to catch  some treds  and  so, For  this  task I  use the  "SC"
spreadsheet  [1], [2]  (to store  the data)  and the  Gnuplot [3]  (for
plotting and curve fitting).

I have been doing this on my Linux/ppc64le workstation and sometimes on
the SDF computers. And I tried to make graphs on amy SGI Indigo, too.

It is  interesting that the  NetBSD (at the SDF)  uses the old  good SC
6.21 (the last "original" version; the IRIX Freeware includes this one,
too) but all Linux distributions (which  include the SC) use its modern
reincarnations (7.x).

The Gnuplot is much more up-to-date  on the NetBSD (6.2). My Linux (the
latest  Fedora) has  just 5.0.  On the  Indigo I  have to  use the  old
Gnuplot 3.5 (something like this is  also available for the DOS, by the
way).

It makes some troubles. In the SC I export the data to text file by "W"
command. Is makes  a simple text file named "covid.asc"  on the SC 7.x.
The  6.21  uses  "covid.sc.asc"  (as  you  got  my  SC  file  is  named
"covid.sc"). So I  the Gnuplot scripts for different  platforms have to
expect  these names.  Of curse  it is  possible to  change the  name of
exported file but it's an extra work for me...

The Gnuplot 5.x  is perfectly compatible. The 3.4 (on  the Indigo) is a
different case. The  Gnuplot syntax changed a lot between  3.x and 5.x.
So I have had to rewrite the  script and to remove the "fit" command at
all  as 3.5  does not  support it.  And the  3.4 on  the IRIX  does not
support export  to PNG or GIF  files so I have  to use the PPM  here (I
want a bitmat picture not a PostScript or LaTeX file which it of course
can produce).

On the SDF  I use the "dumb"  (i.e. text) output to see  how the images
will look like:


                                                                              
                  COVID-19 trend in the Czech Republic                 
                                                                       
 380 +-------------------------------------------------------------+   
 360 |-+  + + + +  + + +  + + +  + + + +  + + +  + + +  + + + + **-|   
 340 |-+New ***A***                                             *+*|   
 320 |Trend #######                                            * +*|   
 300 |-+                                                    A* *###|   
 260 |-+                                                    * A##+-|   
 240 |-+                                                   *###  +-|   
 220 |-+                                                  ##     +-|   
 200 |-+                                      A        ###*      +-|   
 180 |-+                                      **     ##   A      +-|   
 160 |-+                                     *  *####    *       +-|   
 140 |-+                                     *####  *  *A        +-|   
 120 |-+                             A*    ####      A*          +-|   
 100 |-+                            *  #####                     +-|   
  60 |-+                           #####  A                      +-|   
  40 |-+                      #####A                             +-|   
  20 |-+  + + + +  + + #######A**A + + +  + + +  + + +  + + + +  +-|   
   0 +-------------------------------------------------------------+   
     1 2  3 4 5 6  7 8 9  1 1 12 1 1 1 16 1 1 19 2 2 22 2 2 2 26 2 28  
                        Date (from March 1, 2020)                      



References:

[1] https://en.wikipedia.org/wiki/Sc_(spreadsheet_calculator)
[2] gopher://gopherpedia.com/0/Sc%20%28spreadsheet%20calculator%29
[3] http://gnuplot.info