## Die gesammelten Quartz-Regeln zu y-Achsen

Eine der ersten Regeln bei Datenvisualisierungen: Die y-Achse vollständig angeben.

Wer die Regeln, darf sie auch brechen: Quartz erläutert, warum sie nicht immer die y-Achse bis zu 0 anzeigen

„Charts should convey information and make a point. We make charts to illustrate ideas that have context beyond their x- and y-axes. Forcing the y-axis to start at zero can do just as much to obscure and confuse the point as the opposite.“

(…)

First, this is why charts have scales. Blaming a chart’s creator for a reader who doesn’t look at clearly labeled axes is like blaming a supermarket for selling someone food he’s allergic to.

Second, the degree to which the chart emphasizes certain aspects of the data is a judgement of storytelling not chart-making. Sure, this mindset can yield misleading displays, but how is that different than words? Charts should be fair, not impartial.“

Zusammengefasst die fünf Quartz-Regeln zu y-Achsen:

• Truncate the y-axis when small movements are important.
• Truncate the y-axis when zero values are ridiculous.
• Use a zeroed y-axis when it doesn’t matter.
• Always use a zeroed y-axis with column and bar charts.
• Never use a zeroed axis on a log scale.

via @a_sator

## And that is why we need journalists

„If we overload people with the information, and overload them with data and we just focus on the data, we do not provide any further information. So the danger to me is to create fancy visualizations just because you can without really connecting it to a narrative. If you want to provide an additional value, you always need to take data and you visualization and put it into context. And that is why we need journalists.“

## Ah! Deshalb!

Jerome Cukier hat ein Tutorial zu D3 erstellt und ich habe alles mitgemacht, denn er hat mich gleich zu Beginn erwischt.

## copy, paste!

I have learned d3 from deciphering script examples and in the earliest ones one ubiquitous construct was this sequence : select / selectAll / data / enter / append.
It does the work, so like everyone else I’ve copied it and reused very often. It happens to be the most proper way of adding new elements in most cases, but the point is, while learning d3, I (and many people before and after me) have copy/pasted it without understanding it deeply.