Tufte 3 points and a question

~Tufte cites Snow’s map that indicated where the cholera epidemic broke out in comparison to the proximity of the Broad Street Pump. He cites how the dot map was highly effective in showing how localized the outbreak was, even though the map could get “cluttered with excessive detail” (35). I find this interesting since we just read Tufte’s stance on chartjunk, yet he cites Snow’s effective chartjunk.

~“Since it is all evidence – regardless of the method of presentation – the highest standards of statistical integrity and statistical thinking should apply to every data representation, including visual displays” (35).

~Tufte says if displays of data are to be accurate and truthful then the logic of the display should reflect the analysis (53).

Question: The diagram of the O-Rings on page 47 is so confusing and exhausting, why was it used at all for such a serious and dangerous expedition?