Transform Ltd
Colin Hughes
Utility: Graphics
ZX Spectrum 48K

Mike Wright
Chris Bourne

PRESENTATION is an important part of any business when it comes to making a sales pitch or a plea to the bank manager. A visual presentation such as a graph will often make that point clearly.

Histo-graph from Transform is a program which will design bar charts - histograms - and pie charts and print them either on a full-sized printer or a ZX printer.

The program allows you to create up to five sets of data in memory at any one time. Each data set represents one year. In creating a set of data you are asked for a name, a maximum value and a minimum value, the paper and graph colours. Each graph can be shaded in one of three ways.

As the program does not allow the maximum value to be reset downwards it is easier to enter a value below the maximum you are likely to need and to allow the self-scaling feature of the program to adjust it. An interesting bug - it would be a feature if it was documented - adjusts a minimum greater than zero to be treated as the negative value; entering any minimum of 10 actually enters -10. That means that any graph with only positive values must be drawn between zero and the maximum. That produces odd looking graphs if the values are, for example, between 2000 and 2500.

Unlike most graph drawing programs Histo-graph draws the graph as data is entered. A cursor is used to show which bar will be drawn. Once entered, data can be changed easily by repositioning the cursor and entering the new number. It can also be re-drawn as a pie chart.

Initially, the bar names are the abbreviated months - Jan, Feb, Mar - but those can be altered to your own names. There is room at the left of the graph for entering your own text, or the actual values, total and average can be displayed. The values on the vertical axis can be overwritten by the text, while deleting lines of text causes these values to be moved up a line.

For those with colour displays the paper and graph colours can be changed. However, with the Tasman interface and Epson FX80 you can only print graphs which are drawn in black and white.

Two useful features allow a direct comparison of up to three sets of data by drawing all the Jan values together, followed by the Feb values and so on. Alternatively, up to five sets can be drawn one after the other.

All the data, or data for any single graph, can be saved and reloaded. Although reloading data overwrites existing data, the set overwritten by a single graph can be selected. Histo-graph can be saved directly to microdrive.

Competition for Histo-graph comes from McGraw-Hill's Projector 1 which is much more powerful, allowing line graphs and pages of key points to be prepared. The points and graphs can then be run sequentially to form a visual presentation. That program is not as easy to use and cannot be convened to microdrive easily.

The attraction of Histo-graph lies in its ease of use and the methods of display, which are totally different to Projector 1. If you prepare a lot of graphs then you may wish to have both, although you might feel that Histo-graph is overpriced.

Mike Wright

Publisher: Transform
Price: £10.95
Memory: 48K