What is a program chart?

A program chart gives an attractive graphical presentation of courses in a program (or set of related programs), organized by terms or years, linked by pre- and co-requisite arrows, and, when possible, supplemented by timetable information. They are sometimes termed prerequisite charts or prerequisite diagrams, especially when timetable information is not provided.

Who would use a program chart?

Program charts are useful to students selecting courses and planning their programs, and to faculty and staff advising students and managing curriculum development.

The information is already available in calendars and on-line. Why is a program chart needed?

Conventional sources of course, program and timetable information are rarely in a user-friendly format. Faculty and staff advisors, being already fairly familiar with their courses and programs, often do not appreciate how inconvenient it is for students to access all the information they need to make course choices.

For example, program requirements are typically specified as lists of course codes for required and optional courses; one must look elsewhere to find the titles of the courses, the relations between them, their prerequisites, and the timetabling information.

As another example, a course description in a calendar typically specifies what the prerequisite courses are, but hardly ever specifies which course or courses the course is prerequisite to. This information may be very important to a student, but to discover it, he or she must search through all the subsequent course descriptions in the calendar. With a program chart, it is evident at a glance.

As a third example, consider a student who wants to know whether they can defer a course till the following year without risk of timetable conflicts. With conventional sources of information, such a question can be answered only by doing an exhaustive search through both timetable and calendar for a possible conflict. A program chart incorporating timetable data provides the necessary information in a compact and usable form, and the question can be answered immediately.

If program charts are so great, why doesn't every university department have them?

Few academic departments have the resources to produce program charts. If one Googles for "prerequisite diagram" or "prerequisite chart," there are many matches; here are some of these:

Virtually all of the charts on the web are from departments that one would expect to have expertise in technical drawings.

Where can I see PREREX charts in use?

There are charts for both specialized and multi-disciplinary programs on-line here.

What file formats are used for PREREX charts?

The charts themselves are normally distributed in the Portable Document Format (PDF) defined by Adobe; PDFs are readable on any platform and in most browsers using freely-available software (such as the Adobe Reader), printable on any high-resolution printer, relatively compact, and scalable to accommodate paper size, display resolution, or user preference.

On request, we will also deliver charts in Portable Network Graphics (PNG) format for in-line use on a web page. PNG format is also relatively compact and can be rendered directly by most web browsers. Other formats such as SVG (scalable vector graphics) are possible.

PREREX charts are produced by software that processes simple and convenient text-based descriptions. When a PREREX chart is commissioned, the chart description and the key software needed to do the processing are delivered with the chart to allow modifications and updates. This is explained further in the following.

Who owns PREREX-produced program charts?

If you commission PREREX to implement a chart, the chart and the chart description used to produce it belong to you; you decide how, where, and to whom to distribute it.

How can PREREX charts be modified?

University programs and timetables evolve: courses are added or dropped, pre- or co-requisites or timetabling of courses change, and so on. A department will want to keep a program chart up to date, without feeling locked-in to a single source of support. The technology underlying PREREX charts makes it possible for university faculty or staff to make minor changes by editing and re-processing the chart description. On a moderately fast computer, processing is virtually instantaneous, so it is practical to monitor the state of a chart after every change to the description.

All of the software necessary to process, preview, print out, and convert PREREX charts is open-source and legally downloadable from web repositories (or, if desired, available from commercial suppliers), runs on all platforms, and is easily installed. Complete details are given in the Maintenance Manual for Program Charts.

Use of a separate text-based description file and intelligent processing software make it easy to modify a PREREX chart. If the text within a course box is changed, the size of the box, the length of connectors to and from that box, and the location of arrowheads into the box are all adjusted automatically by the processing software. If a course box must be moved, it is straightforward to edit the relevant instructions for arrows into or from the box because the coordinates specified for an arrow are those of the box centres, rather than those of the edges or corners of the boxes. Small changes can be made with any text editor, such as Notepad. For more substantial changes, an interactive chart editor is available; it supports add, remove, cut-and-paste, and edit operations on diagram elements, and shifts of an entire diagram. The effects of these operations may be observed, after saving and re-processing, in a PDF viewer, without exiting the editor. Editing a text file in either of these ways is far easier and faster than trying to fiddle with an image using a mouse.

If a client is unwilling to maintain their charts themselves, we provide an optional support service.

What software is used to produce PREREX program charts?

To process the description of a PREREX chart, the following software is essential:

  • an up-to-date standard-conforming implementation of LaTeX, such as the "basic" MikTex distribution for Windows systems;
  • a file prerex.sty of specialized LaTeX definitions;
  • a few additional LaTeX packages, such as pstricks.

All of these items are readily available in web repositories around the world and easily installed. For example, the MikTeX package manager will actually download and install all needed standard packages automatically the first time a chart is processed.

The following additional software is optional but recommended:

  • a lightweight PDF viewer, such as GSview;
  • an integrated LaTeX development environment, such as Texmaker;
  • suitable fonts, such as the URW-Classico implementations of Optima and LaTeX support files available here (files uop.txt and uop.zip).
  • the prerex interactive editor for PREREX charts; this can easily be compiled for use on any Unix-like platform, such as Linux, Solaris, Cygwin on Windows, Fink on OS X, and so on.

Why couldn't I use a program like Visio® or CorelDRAW® to produce a program chart?

You could, if you have such a program available, are very skilled in its use, have the time to produce the desired chart, and won't be embarrassed distributing a chart that looks amateurish. Look carefully at a PREREX chart and notice the following properties:

  • Each course box is sized to just enclose the text within it, with uniform standard margins.
  • Each arrow between courses is oriented from box centre to box centre, rather than from/to standard "connection points" on the box edges.
  • The arrows are "clipped" by the course boxes, but the arrow heads abut the target box exactly.

These desirable properties are not easily achieved using conventional "do-it-yourself" drawing software, no matter how "user-friendly" it purports to be.

The technology we use provides complete flexibility as well as professional quality:

  • Text within a course box may be partitioned into regions with varying characteristics. For example, the course code and the timetable information on the first line of course boxes are in a smaller font than the course name. The latter is centered and the former are left- and right-justified, respectively.
  • Any available Type 1 (Postscript) or TrueType format fonts may be used; in the charts linked to above, the typeface used is FrutigerNext, a very legible sans serif face. The professional-quality typesetting engine takes advantage of kerns and ligatures in the fonts.
  • Line thickness for boxes may be varied; in the example diagram, heavier boxes (and bold-face text) are used to indicate that a course is "required" in the program, rather than an option.
  • Different styles of connectors can be used, for example to distinguish pre-requisites, co-requisites, and recommended pre-requisites.
  • Various sizes or shapes of course boxes may be used, for example to distinguish between half and full courses.
  • Graphic images such as logos can be imported.
  • Colours and hyperlinks to on-line course descriptions or calendars are possible.

Wouldn't a commercial drafting service be able to produce a professional-quality program chart?

Possibly, but you will almost certainly have to do the global lay-out yourself. A more serious long-term problem is that it is unlikely you will be able to maintain the chart yourself using freely available software. You will be "locked-in" to use the drafting service for every future modification of the chart.

How much does a PREREX chart cost?

Our rate for producing or editing charts is $100 per hour. Each chart is unique, but production of a chart "from scatch" typically requires two to three hours.

What does one get with a PREREX chart?

A chart package as delivered consists of the following files in a zipped archive:

  • the chart itself, in PDF;
  • the chart in PNG format (if requested);
  • the source file describing the chart, to allow editing and updating;
  • a file prerex.sty of LaTeX definitions supporting the production of PREREX charts;
  • a chart "maintenance manual," which has detailed instructions on how to install and use the software necessary to edit and process the source file in order to produce updated or modified charts.

How do I contact PREREX?

Reach us by e-mail at info@prerex.com.