8. CHARTS

PICTURE OR DESCRIPTION?

Charts are a way of representation that's very clear to a sighted person, to take in at a glance, the best way of showing certain data; to a blind reader, however, a list of numbers is far easier to read and understand. So should we transform all charts into tables? Firstly, the blind reader then will never learn how to read charts, so all braille producers should agree on their transformation into text. Secondly, some indescribable charts are left, hard to understand as the reader is not familiar with the basic type. And thirdly, isn't reading charts part of the secondary school's curriculum?
We should cut down in drawing charts, especially in non-educational or post-secondary school texts, but that still leaves a lot of charts to be drawn.
I am aware of this discussion contradicting my argument in the introduction about editing for the blind. Still waiting for a unified theory.

In general, the information in a bar is in its length, width doesn't matter: so go for a comfortable width like 2cm, if space allows. On the other hand, a bar chart intends to compare, so if possible keep it to one page. Sometimes it's best to make a line chart out of a bar chart.

A simple bar chart just has some bars in a coordinate system like axes in graphs: in many ways, bar charts are like graphs. Draw axes at 1mm width; draw the bars' outlines in a fat line, like 2.5mm. Now the chart is still just a collection of lines, but filling in the bars with thin lines that also work as reference lines (horizontal in vertical bars, vertical in horizontal bars), and ideally at a distance from each other within the fingertip window is a beautiful solution. It suggests a numerical value. If possible, have an axis-width line at axis-numbers height or width.
Don't put grid at the outside.

    Basic Bar Chart, Fill in Bars with Lines (ca 50K)

Charts are often decorated by lifelike elements, or drawn in emblems of their subject matter: to the blind these are not amusing. Again we'd best render them in a uniform way.

    Edit Fancy Picture to Standard Chart
    inkprint (ca 25K)
    Braille (ca 70K)
    Funny Charts for The Sighted (Inkprint Only)
    one (ca 100K)
    more (ca 140K)
Estimates or projections may not look like the other bars in a chart: for us a uniform rendering is better.
    Draw all bars in the same way (ca 60K)
Vertical bars make writing, identification easier, for there is usually only room for two or three Braille characters under a bar, so rotating vertical bars might make the chart easier to read.
    Move bars from vertical to horizontal
    inkprint (ca 35K)
    Braille (ca 55K)
Some bar charts have clusters of different bars: try to hatch the largest bar in reference lines. This kind of chart often has half-hidden bars: bring these out in the open like all other bars.
    Edit to Uniform
    inkprint (ca 30K)
    braille (ca 50K)
Other complicated bar charts have bars divided in sections: choose hatch- type by expediency, like small sections solid black. In this kind of chart it's often better not to have a fat outline, as its top might look like a bar section. Enlarging details on a separate page is a possibility here; mark clearly which part you're going to show in detail.
    Two-variables bars
    inkprint (ca 15K)
    Braille (ca 70K)

Again sometimes we'll have to juggle: rotate, mirror etc. to get a clearer picture; sometimes go for a description of a complicated chart, but in those cases it might be nice still to draw a part of the chart and an overview, or a simplified version, so as to give the blind reader a notion of its inkprint graphic representation..

    A Complicated Chart
    inkprint (ca 70K)
    Braille, part 1 (ca 35K)
    Braille, part 2 (ca 60K)
Maps containing charts are usually for decoration, but occasionally show locations relevant to the bars: in that case we split up in a separate map and chart.
    Chart in A Serious Map
    inkprint (ca 40K)
    locations map (ca 50K)
    chart (ca 30K)
Pie charts follow the general chart guidelines, but allow for more writing in the sections, which may be useful.
    A Pie Chart Example
    inkprint (ca 40K)
    Braille part 1 (ca 35K)
    Braille part 2 (ca 70K)
    Other Inkprint Examples (ca 40K)
Population pyramids can't be described satisfactorily, as it will take a lot of imagination to relate a group of numbers to a shape; so we'll have to draw them, and in a standard way.
    Population Pyramids
    inkprint (ca 30K)
    Braille (ca 55K)
    another one (ca 60K)

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© 1989, 2002 Marco Schuffelen All rights reserved

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Last modified: Thu May 15 10:34:12 PDT 1989