Tuesday, September 6, 2011

Goldilocks Maps: Enough Info but no more

Introduction: There are Goldilocks planets (not to hot, not too cold, just right) and Goldilocks economies (moderate inflation, moderate growth). I want to propose that we aim for producing goldilocks web maps: Not too little information, not too much, but just enough. 

Finding Cafes Problem: A web map example is using satellite imagery or a road map as base data in a mash up.  Satellite imagery has lots of information people find interesting, like who has the biggest patio in their neighbourhood (below left). 

However, if you're on your iPhone trying to find somewhere to eat (cafes in the above map are red pins or dots) you don't want the visual complexity of seeing patios or even gardens.  You want to see a road map mash up (above right), where the only information is the cafe locations, roads and road names.

Related Web Map Design Issues: It's not just base data this applies to, there are a number of web map design topics where  we should be actively thinking 'have I got the information balance right here'.  Examples include:
The Goldilocks web map concept is related to Edward Tufte's idea of 'chart junk': any pixels not directly showing data or helping show data (e.g. a key) are junk and need to be removed.  

A lovely idea for a map but full of chart junk.

There's more of an argument for putting too much information into a map than allowing it to contain chart junk. Extra information, by definition maybe useful whereas junk is, well, junk.  For example, we could add other data layers to the cafe map by splitting the cafes into vegetarian, greasy spoon and coffee bars.  Its more complex to understand but will be important for vegetarians.

For most maps the concept of chart junk holds true but I recently posted ideas about when chart junk has a place by discussing the flashiness of Google Earth Tours.

London tube map:  This is the perfect example of a Goldilocks map, 

The Modern Tube map is shown on the top and the real station locations are on the bottom.  The Circle Line is in yellow and has been distorted from reality on the tube map to improve clarity.  Other distortions to improve clariry include making lines vertical, horizontal or at 45 degrees .

Harry Beck's genius was to realise that when navigating within the tube system the true locations of the tube stations is information that can be left out, users can navigate perfectly well given just lines and node information.  This means the actual locations and distances on the map can be distorted in order to improve the clarity of the map.  E.g. the area inside the circle line (yellow above) is expanded, it has a high concentration of stations and expanding them makes the station labels easier to read. The idea has been copied for transport systems the world over making it very familiar today but it isn't hard to imagine people's initial reactions:  A map that doesn't show locations properly?  What good is that? Dismissed by the authorities at the time when released it to the public it proved very successful and it is now, rightfully, a design classic.

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