Visuale

Nice quote about the unfamiliarity of cartograms here:

Their main disadvantage is that they are unfamiliar, but we do not learn from familiarity

Here is a nice one depicting US elections:

What is a cartogram? In the author's words:

The basic idea is to distort a map by resizing its regions according to a statistical parameter, but in a way that keeps the map recognizable.

More info here.

I came across this nice book: "Designing Interfaces" the other day.

Even if not explicitly stated in the title, its main content is design patterns for user interfaces, that is, a list of common design problems often encountered by UI designers whose typical solution is captuted by the pattern. Information is organized around a standard template (in the typical pattern language style) containing: what, use when, why, and examples.

The author is Jenifer Tidwell. She has done extensive work on UI design patterns since 1997 starting with her MIT page Common Ground.

Even if it doesn't seem to be directly related to infovis I think it is a great resource to decide how to compose a user interface around a visualization system. In my opinion, too often it's forgotten how important the interface around a visualization is and the key role standard interactive tools play when connected to the visualization.

The pattern language contains also a nice group of patterns entitled: "Showing Complex Data" which doeas exactly for our case. The patterns are:

• Overview Plus Detail
• Row Striping
• Sortable Table
• Jump to Item
• Cascading Lists
• Tree-Table

It's nice to note how visualization and user interface design cross-fertilize each other. Techniques like overview+details have had a big role in visualization but they are more and more used now user interfaces in general. At the same time, many visualization tools are integrating more and more standard UI components like sortable tables and tree-tables as they are very effective and often outperform any other fancy custom-made solution.

Nice simple and plain post from statgraphics.blog.com, explaining what histograms are and why they are different from barcharts:

Histograms are often mistaken with barcharts. The fundamental distinction between the two is:

• Barcharts show counts (or weights) for the discrete axis of a categorical variable
• Histograms show an approximation of the density function (if scaled accordingly) of a countinuous variable.

Histogram	Barchart

That's absolutely right, even if I didn't ever realize it, I used to mix the two names up too.

And there's more:

As a consequence, the only thing that can be quantified in a barchart is the bar height ... On the other hand, in a histogram, the area of the boxes is proportional to the density approximation. If all bars have the same width in a barcharts, or gaps are drawn in a histogram (which is complete nonsense), the two plots can get mixed up.

I would also add that another consequence of that is that the values in barcharts can be reordered to show different patterns. The most common ways are: order by frequency or alphabetical order, but there can be others available.

Barcharts and histograms does not look "cool" enough but they are among the most powerful visualizations available. If used properly, they can convey a lot of information in a compact and effective way.