This is a graphs and charts package aimed, apparently, at people
who own high resolution monitors (Mode 0 displays throughout) and
printers, but no disc drives! The programs can be transferred to
disc but need to reside at &E00. The usual downloading tricks leave
the disc system disabled for saving and loading data files. All
accompanying documentation suggests that the system is designed only
for tape storage; disc users being instructed to *TAPE and reset PAGE
to &E00, etc.
Turning to the programs themselves, there is a short INTRO which must
be loaded prior to the other programs, which sets up user-defined
graphics and an Epson screen dump routine. The other three programs
are UNIDATAM, BIDATAM and MULTICART.
The first of these displays either histogram or pie-chart displays of
a single set of data. I quickly discovered that the data must be
totals or averages of different categories - the program does not
process raw data. In the pie-chart option the data is, however, rescaled
to the extent that percentages are printed in the sectors. You may also
enter labels which are printed around the chart in appropriate places.
In the histogram option the data is presented as vertical bars in the
order in which you typed them in. You have options for user-defined or
auto-scaling, and for a horizontal and/or vertical grid display of the
scale used.
A nice feature is the legend option, which allows you to move a
cursor around the screen printing labels wherever you wish. You may
save the data (to tape) or even a 20K screen dump which, though much
slower, does preserve the legends, etc.
BIDATAM has similar features, except that one enters data as x/y
pairs. A Cartesian option simply draws a graph by joining up successive
points with straight lines. A so-called "Regression" option draws instead
the best fitting straight line function.
In fact, this is the correlation, not the two regression lines, which allows
compromise predictions of x from y and vice versa from the same graph (the
program will compute these for you). MULTICART allows you to draw multiple
Cartesian graphs by defining several sets of y scores corresponding to one
set of x's.
The Mode 0 screen sacrifice colour for accuracy and the main use of this
package seems to me to lie in producing hard copy on a printer, rather than
on-screen displays. The legend writing facility assists greatly, and a number
of impressive screen dump examples are provided at the end of the detailed
documentation.
The screen dump provided "wil work for the Epson RX-80 printer, and probably
many other printers". Well, I tried in on one of the popular "Epson compatible"
dot-matrix printers, which normally runs Epson graphic programs, and it crashed
(it did work on an Epson FX-80 though). The programs are not protected so you
can substitute your own screen dump routine. However, this requires programming
expertise in a package designed for people who want to use software rather than
write it.
There is much that I like in this package, but there is an undeniably
amateurish feeling to it. The press release with the review copy indicates that it
is aimed at scientists and businessmen. Someone should tell the company that
such users do not mess about with tape recorders. If they want to make any
impact with these programs they must produce a disc-based version and a screen
dump routine tested on a wide range of printers.