Visual information is often about comparison. Comparing levels of a graph. Comparing distances on a map. Comparing colours on a heat map.
We see by comparing one piece of stimuli with another to decide what is in front, behind, moving.
I recently found a book I used to have when I was young. It is called Comparisons and is by The Diagram Group. It uses different methods to compare different things, weights, people, buildings, units.
I have photographed some of the spreads for discussion here.
The first set are what I would call Scaled Comparisons. They ask you compare two visual properties drawn to scale on the page.
They may be objects that are not typically associated with one another - but they only require us to understand one in order to reflect on the other.
It helps if the one that we start with is familiar to us. A man, a cat, a pen, something we know and can use as a measuring device.
The above spread uses Central Park, NYC, to show the distances runners cover - a nice idea if every one was familiar with central park - although the park/joggers association is nice
World Rivers stretched across the US works - even more striking is the juxtaposition of the Nile across Europe, below
It is a shame that the vehicles are not to scale with the people that fit in them - the London Taxi may be - but the planes and boats aren't - the graphic is torn in two ways - showing capacity of passengers and scale of vehicles - I think both are interesting and both would be possible (just don't show the whole boat?)
Life-size scale illustrations have a visceral power and accessibility - the ruler is a sound touch to remind us of this. Maybe bringing in a domestic or schoolroom tool such as a ruler, these 'escaped' insects seem even scarier - the object that you are comparing it to can bring an emotional meaning as well as a quantitative scale - it's why lazy journalism that compares everything with buses or elephants seems glib - people don't just compare the scale - they look for an association between the meaning of compared objects
The next set are what I would call Stepped Comparisons. They ask the reader to understand one concept of measurement and then apply it, often in many steps to the concept. It is a lot harder to get these to work. I imagine that many people can understand the scaling of a matchbox to a box of cereal, then to a car, a room, to a house and possibly to a street, but when the steps are too many or leave the realm of the known, then people can get lost.
This discusses distance - not unlike The Powers of Ten. I think the Powers of Ten film is more impressive for two things - animation smooths the stepping of scales and the voice-over that keeps us paying attention and referencing previous steps.
This spread and many of the stepped ones lose me after a few steps.
This one looks at volumes, again, starting slow, we are ok, but soon lose our way. I wonder if the latter steps, dealing with the larger quantities need to retain some of the visual cues and reminders of the smaller state/ known quantities
This last one deals with historical events - I am not such a fan of this - i think the spiral is an interesting motif - but unrelated events can be associated by proximity as they pass each other on the spiral. It does of course make a time-line easier to fit into a book, but we are in the business of explanation, not fitting things in.
More examples of comparisons from current media can be found at Chiqui Esteban's blog - Infographics News.