Monday 12 October 2015

Principles of cartographic design

I was following an email discussion late last week regarding the search for some online principles of cartographic design. Many exist in various books that those with a cartographic background are aware of but, of course, people prefer to want their information for free via their glass lens on the world. Actually, there aren't many online. Ordnance Survey have some here which are certainly worth a look but it's still books that get into the detail you'll need if you're going to really learn about cartography.

Some see principles as rules but that gives them a status of authority and absoluteness that suggests they shouldn't be broken at all, at any cost. There are some rules in cartography (such as which govern effective text placement; or to process data into a rate for a choropleth map) but I see principles as guidelines that provide oversight for the map you're making. I'm happy for them to be challenged and broken and innovation often comes from that process. I'm also strong of the opinion that if you know some principles you're in a good position to also know when and how to challenge them in your design. You'll also be able to easily recognize when a map eschews principles and simply fails.

One of my friends from the UK, Alan Collinson (of Geo-Innovations) reminded everyone in the discussion of the principles that the British Cartographic Society Design Group drew up some time ago. I'm guessing this would be the late nineties or thereabouts. I have a vague memory of them at the time but the internet wasn't then what it is now and these ideas tend to get lost. Many good cartographic minds and practitioners conceived of them so I thought it worth posting them here, as is. Some may find them helpful. Interestingly, the principles are prefaced with three statements and as you read through you can see the underlying current of fear about the spectre of GIS as a threat to cartographic design. Perhaps the parallel now is the threat to quality by ubiquitous citizen mapping?


The purpose of cartographic design is to focus the attention of the user.
The Principles of cartographic design are timeless, the results are not.
The rules of cartographic design can be taught and can be learnt, principles and concepts have to be acquired and practiced.


Without a grasp of concept the whole of the design process is negated.  The parts embarrass the whole. Once concept is understood, no design or content feature will be included which does not fit it. Design the whole before the part. Design comes in two stages, concept and parameters, and detail in execution. Design once, devise, design again User first, user last.  What does the user want from this map? What can the user get from this map? Is that what they want? If a map were a building it shouldn’t fall over.

Important things must look important, and the most important thing should look the most important."They also serve who only stand and wait". Lesser things have their place and should serve to complement the important. From the whole to the part, and all the parts, contributing to the whole. Associated items must have associated treatment. Harmony is to do with the whole map being happy with itself. Successful harmony leads to repose. Perfect harmony of elements leads to a neutral bloom. Harmony is subliminal.

Great design tends towards simplicity (Bertin). Its not what you put in that makes a great map but what you take out. The map design stage is complete when you can take nothing else out. Running the film of an explosion backwards, all possibilities rush to one point. They become the right point.  This is the map designer's skill. Content may determine scale or scale may determine content, and each determines the level of generalisation (sacrifice).

Maximum information at minimum cost (after Ziff). How much information can be gained from the map, at a glance? GIS has forced cartography into one of its utility phases, the necessary information but without visual interpretation. What we need is functionality, not utility.  Design makes utility functional.  Design increases the information transfer process because a
well designed map has clarity.  Clarity is achieved by compromise. All designs are a compromise.  A compromise between what could be shown and what can be read and understood.

Engage the emotion to engage the understanding. Here is the crux for all GIS Systems.  The one thing that cartographers acknowledge when creating maps is that it takes something out of them. They have expended some invisible emotional energy in the act of creation. When a GIS system cries over its map then I believe we cartographers will be defunct. Design with emotion to engage the emotion.  Only by feeling what the user feels can we see what the user sees. Good designers use Cartographic fictions, Cartographic impressions, cartographic illusions to make a map.  All of these have emotive contents. The image is the message. Good design is a result of the tension between the environment (the facts) and the designer. Only when the reader engages the emotion, the desire, will they be receptive to the maps message. Design uses aesthetics but the principles of aesthetics are not those of design.  We are not just prettying maps up.

There you go...maybe we should think of updating them? Actually, I a book I'm currently writing with Damien Saunder called 'Cartography.' A book. Not a web site. We're excited by it...a modern book on cartographic design that delivers principles and practical advice. As of today we're about half way through writing it and hoping it'll be published by the middle of next year.


  1. It can be an uphill battle getting GIS people to take design seriously. On the bright side, there's definitely a hunger out there for learning material that integrates design and GIS, rather than dividing them.

    I presented my attempt at this last month at Ozri (missed talking to you, Ken; didn't know you were just there for one day). Here's a cut-down version of my presentation with some links and resources at the end

  2. Was hoping there'd be some reference to the Clint Eastwood squint test under Number 2. Fond memories :-) - enjoyable read as usual!