Improve bar chart display of actual versus ideal

[morungos]

Applies to bar graphs in Summary charts:

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When you hover over a bar graph with your mouse, you see figures for 'actual' and 'ideal’ but there’s no other way of seeing these figures except with mouse control.

It might well be that d3 would be better here, except it is not portable. Maybe protoviz would do.

[morungos]

The best representation appears to be the bullet chart. See http://www.perceptualedge.com/articles/misc/Bullet_Graph_Design_Spec.pdf for the specification. This is designed to measure a value against an ideal, and it allows us to do some imaginative stuff too, like actually putting qualitative measures in too. The qualitative measure that makes most sense is a chi square goodness of fit, to test whether there is significant deviation from the ideal value.

[morungos]

There appears to be no viable charting component for bullet charts that works on all browsers. I've played with several, and most require huge effort to retrofit bullet charts into something that they aren't at all similar to. Probably best to start from scratch aiming to do do progressive enhancement with RaphaelJS

[morungos]

The new bullet graph tool is now implemented and seems to be working well as a visual representation.