Monday, January 31, 2011

Circles on maps

Last Friday I was at the excellent Design of Understanding conference at St Brides. David McCandless gave a very good presentation of the thinking and process behind his Information is Beautiful website and book.

A common technique used by David McC, and the various newspapers represented at the conference, is to vary the sizes of circles used to represent different quantities. At one point Mark Barratt asked the question on a lot of people's minds: hasn't it been established that circles are a pretty unreliable way to compare quantities? I'm not sure it would be fair to say he was brushed aside - perhaps the background to his question wasn't really understood.

Doubts about circles go all the way back to Willard Brinton's 1916 book Graphic methods for presenting facts. Perhaps further.

Brinton's explanation shows, first, the well-known difference between using diameter and area - diameter hugely exaggerates differences. However, he goes further and condemns even circles that compare areas, pointing out that they have the opposite effect - we tend to underestimate the area of the larger circle. His conclusion: 'Horizontal bars have all the advantages of circles with none of the disadvantages'.

In his 1956 PhD thesis, James Flannery proposed a correction formula, so that the perception of the difference would be correct, even if the actual area of the circles is not. Several other people researched the same issue and came up with similar findings to Flannery's (apparent value = actual value * 0.86).

Unfortunately for seekers after simple solutions, Hans-Joachim Meihofer then showed that individuals varied too much in their judgements for Flannery's formula to be reliable. However, he demonstrated that the whole problem could be solved by using stepped sizes of circle and providing a scale.

The story is well told in Michael Macdonald-Ross's 1977 review 'How numbers are shown'.

Unfortunately it is not quite as simple as that - Patricia Gilmartin went on to demonstrate how important context is when viewing circles of different sizes (demonstrated through the well-known Ebbinghaus illusion). The centre circles are the same size. Oh dear.

My personal view is quite relaxed - I see circles on maps as simply relative and I don't expect to derive actual data from them. I am happy to see them as approximate (tiny vs medium vs huge). However, I have great respect for those who see statistics as sacred, and yearn for integrity in presentation...  which brings us to Michael Blastland's excellent presentation at Design of Understanding. He rendered this whole discussion somewhat irrelevant by questioning the reliability of so much of the data used for apparently simple charts in newspapers. And he reminded us that statistics is as much about probability and uncertainty as about facts - a view enshrined in the title of Howard Wainer's latest book on quantitative graphics: Picturing the uncertain world.

Michael's Go Figure articles on the BBC website should be required reading for information designers.

  • Brinton W.C. (1916) Graphic methods of presenting facts. New York: Engineering Magazine
  • Flannery J (1971). The relative effectiveness of some common graduated point symbols in the presentation of quantitative data. Canadian Cartographer, 8(2), 96–109.
  • Gilmartin, P. P. (1981). Influences of map context on circle perception. Annals of the Association of American Geographers, 71(2), 253-258.
  • Macdonald-Ross, M. (1977). How numbers are shown – a review of research on the presentation of quantitative data in texts. AV Communication Review, 25(4), 359-409.
  • Meihoefer, H. J. (1969). The utility of the circle as an effective cartographic symbol. Canadian Cartographer, 6(2), 105-117.
  • Wainer, H (2009). Picturing the uncertain world: how to understand, communicate, and control uncertainty through graphical display. Princeton University Press.

Dumped on the beach wet through

I've been going through a pile of old notes, rather alarmed at how little my thoughts have moved on from what was pre-occupying me fifteen or twenty years ago. One note, probably made during a conference presentation, caught my eye. I'm assuming it is something I had just heard someone say, rather than something I made up. It's about the concept of surfing the web, and it points out that surfing is extremely difficult and ends up with everyone being dumped on the beach wet through.

Tuesday, January 11, 2011

Return of the widow

I am addicted to my iPad, and I particularly enjoy reading newspapers and magazines again, free from annoying links and comments from crazy fellow-readers (otherwise known as Web 2.0). They are starting to restore page layout.

However, you have to get used quite a bit of careless editing - for some reason, more typos than the paper versions, headings that revert to plain type, references to pictures (right) when they are in fact somewhere else. And spectacular widows - particularly in The Times and The Economist (see above... well, OK, below).

Monday, January 10, 2011

Celebrating Rupert's 90th

I have developed a minor obsession with the layout of the Rupert Bear annual, a favourite of my childhood. I've mentioned before the parallel layers that suit different readers (and I have written a short piece for Eye magazine to be published this month). Last year was the ninetieth anniversary of Rupert, and it's been marked by one or two publishing events.

The Life and Works of Alfred Bestall: Illustrator of Rupert Bear is the biography of the longest serving of Rupert's creators, by his god-daughter, Caroline Bott. His archives are going to the Bodleian in Oxford, who recently put some of the work on display. It is very much a biography of the man – very interesting, but Rupert is only part of the story, and little is revealed about the origin of the layout.

More informative about this is The Rupert Companion, by Ian Robinson, one of the last of Rupert's editors. This is a wonderful book, designed by Faye Dennehy in a generous format that allows the illustrations to breathe. It's very readable and takes us through the whole story from Rupert's originator, Mary Tourtel, to Bestall, and more recent editors and illustrators. I hadn't realised that it was the sale of the Daily Express, where the Rupert strip appeared, to Richard Desmond that finally did for Rupert in 2002, although old stories continued to be recycled.

The layout I've been celebrating dates from the Rupert Annual of 1936, and was the responsibility of the Daily Express's children's editor, Stanley Marshall. Mary Tourtel had written four lines of verse under each drawing, but Alfred Bestall found that rather challenging and moved the format of the daily strip to prose. This also meant he could develop better dialogue for the individual characters. But in the annuals Marshall included both prose and verse, now in rhyming couplets.

Tuesday, January 04, 2011

Venice of the North? Join the queue

Clicking some news links I somehow ended up with a story about the floods in Australia: 'Rocky the Venice of the North'. Overlooking the fact that Rockhampton would surely be the Venice of the South, they need to get in the queue. I've lost count of the cities I've visited that make that claim, but I've yet to see Venice reciprocate, and boast of being the Birmingham of the South. Or Stockholm. Or Amsterdam. Or Bruges.

15 minutes with Google I'll never get back, and here's a list of other contenders.
  • Aalborg: Paris of the North
  • Abidjan, Paris of West Africa
  • Amsterdam: Venice of the North
  • Asheville, North Carolina: Paris of the South
  • Belfast: Athens of the North? (to be fair, this course at Queens University, Belfast, comes with a question mark)
  • Bogotá: Athens of South America
  • Boston: Athens of America
  • Bourton-on-the-Water: Venice of the Cotswolds
  • Buenos Aires: Paris of South America
  • Coimbatore, Manchester of South India
  • Edinburgh: Athens of the North
  • Fort Lauderdale: Venice of America
  • Freetown: Athens of West Africa
  • Manchester: Venice of North
  • Philadelphia: Athens of America.

So we all want to be Athens, Paris or Venice. Except that Coimbatore is keen to be the Manchester of South India. Given Manchester is the Venice of the North... well, you can see where this is heading.