Geoff Bains casts an eye at Minerva's new package System Gamma for creating graphic displays from your database.

When Minerva launched the System Delta database language/package last year (see Beebug Vol. 5 No. 4) the one thing missing was a good way of displaying the data sorted and searched for. True, the data could be got at quite easily and used with a Basic program to draw a graph or chart. However, that relies on the same programming skills which System Delta was designed to render unnecessary. Now Minerva has followed the tradition of System Delta with a data presentation package called Svstem Gamma.

Again the package is a programming language with a series of star commands to manipulate data and create displays on the screen. As with System Delta, when you purchase System Gamma you are not actually told how to use the programming language. It is not easy to guess it all either, as there are a great many star commands (such as SGOPT, SGdefine, SGxscale, SGfont, SGaxis and SGgraph), not to mention a myriad *FX163,18,n commands, which are near to impossible to fathom without help.

All the information to actually program your own graphics presentation package is contained in the System Gamma Programmer's Reference Guide. Unfortunately, as with System Delta before it, this will set you back a further £19.95.

I can't help feeling this is both a bit of a con and extremely silly. If the guide is written and printed, it costs very little more to include it (in presumably large quantities) with the software. This habit of Minerva's is not one we should look to encourage.

The documentation you do receive with System Gamma is the manual for an application already written. To be fair, this program does allow you to present displays of data entered by hand or imported from ASCII files, or from System Delta, in just about any way you would want. This program will suit the majority of people as it is.

However, if you want to import data from something a little more exotic, you will have to write your own program or modify the ones given - and we are back to the Programmer's Reference Guide again.

System Gamma is supplied in a 32K EPROM which plugs into a normal 8/16K ROM socket thanks to a small carrier board of the Computer Concepts type. The ROM is compatible with all types of BBC micro but requires shadow RAM for extra memory and the Acornsoft GXR graphics extension ROM for some of its fill patterns. These can both be either built in from the start (as in the Master) or additional items to your model B micro.

Unfortunately, although the programming language is happy with, say, an Aries board for shadow RAM and a plug-in GXR ROM, some of the opening sections of the applications program are not - they require a little rejigging to get the program to run. It is not hard to do but rather defeats the purpose of ready-written software. In addition, the different on-screen fonts are not always available with a model B system.

The applications program provides graphics displays of any data in a number of different graph forms. These are simple histogram, '3D' histogram, pie chart, scatter diagram and line graph. The whole program is centered around a rather peculiar menu-and-additional-single-keypress driven module which will be a familiar style to existing Minerva software users.

Data for the graphs is entered into a simple table providing for a label and two values for each entry. Each entry's section of the resulting graph can now also be defined in a specified or automatically selected colour and highlighted or not - the way the highlighting is done depends on the graph type but all are effective.

The type of graph is also specified on this table, along with the font used for the axis and entry labels (normal, small or thin), and flags are provided to display an outline, percentages, values and labels, and are toggled with Ctrl-letter keypresses. The whole table is easily and quickly drawn up for any particular graph required. This data can then be saved to disc or altered with the simple and effective editor.

Data can also be imported into the program from other software (most likely a database or spreadsheet) as long as it is in an ASCII file and takes the form [label], [x-value], [y-value], [label], [x-value], [y-value], etc. Many programs can produce such data, and it is relatively simple to write a short Basic program to convert other software's data to this format or to generate such data to start with. For System Delta data a special program is provided for stripping the required data from the Delta index cards.

Once the data is entered it can be instantly displayed in the type of graph format chosen, and some further manipulation performed on the screen. The graph can be changed in size (and to some extent shape), and shifted around the screen. It can be printed out or the screen saved to disc for further additions later.

For graphs which plot two values for each entry (scatter and line, not histogram or pie) the line of best fit can be instantly plotted on the graph, and the equation is given on the prompt line at the bottom of the screen. Complete statistical analysis of each graph can also be performed by the program. The minimum, maximum, line of best fit, mean, standard deviation and correlation coefficient are also displayed nearly instantaneously and can be output to a printer if required.

Several graphs can be in memory at a time, and with more than one the ability to shrink graphs and move them around the screen becomes a vital one. More than one graph can be drawn on the same screen, at any size or relative position. Again, the multiple graph screen can be printed or saved to disc.

For that final touch of professional presentation, text can be added to the complete screen in any position inside boxes of various designs and in the same range of fonts as are provided for axis labelling. Lines can be drawn to divide up the display and graphs boxed and shaded to give a professional look to the whole screen. Again the finished screen can be saved or printed.

Of course, the same set of instructions will often be used to produce similar graphs from different sets of data or to update a graph of cumulative data. To make this much easier, System Gamma is also provided with a macro facility. All the operations of the system can be defined in a simple program (which basically uses the System Gamma star command language, without the stars) and the program saved to disc.

Useful additions such as prompted waits for a keypress are included, so a complete 'slide show' presentation of many graphs can be put together for near-automatic display.

There is nothing that System Gamma does which any reasonably competent Basic programmer with a little elementary geometry couldn't manage on their own. However, this package does it all for you and at a speed and with a flexibility which are hard to match.

The lack of inclusion of a real programmer's manual is a grave omission, but even without it System Gamma provides a powerful all-purpose data presentation package which will prove well worth the price to anyone struggling with the Beeb for business.