Archive for September, 2011

13
Sep
11

Assembly-Line Map Elements

Gentle readers, my apologies for being so long in returning to blogging. Inspiration has sometimes been a bit lacking, and when it wasn’t, time was. But be assured I have no plans to abandon this enterprise without notice, though I may take breaks from time to time. I’m also hoping to bring back guest posts to keep things going when I don’t have the time.

On to today’s main event. This morning I received an email from a colleague pointing me in the direction of the GIS Lounge, specifically the recent post there entitled “Ten Things to Consider When Making a Map.” It’s a well-intentioned piece — many people out there who are just starting out begin with the question, “how do I make good maps?”, and there are several other forums and websites out there which give aid to the uninitiated. Unfortunately, the GIS Lounge chose to give the following as one of their pieces of advice:

6. Incorporating Map Elements

Making sure that all map elements are properly applied is important for providing readers with the context of the map.  All maps should have a clear and concise title, scale bar, and north arrow.

I can think of few more misguided statements about cartography. Longtime readers know that I am the head of the Worldwide Campaign to Eliminate Needless North Arrows, as well as the International Crusade Against Useless Scale Bars. Such elements often end up as no more than functionless clutter, yet we are told that they are mandatory all the same. If you click on the link above, you’ll be taken to the GIS Lounge’s list of “required” map elements (edit: shortly after I made this post, the page was changed to no longer call them “required”), including scale bars, north arrows, and legends. To be fair, the GIS Lounge is by no means alone in advising that there are certain things that every map simply must have — such declarations are unfortunately not rare. However, their “What’s in a Map” post is probably the most prescriptive one I’ve seen in a good while.

To begin, the entire concept of a list of “things you must do to make a proper map” is deeply, fundamentally flawed. It’s as misguided as a list of “things you must do to make a good painting,” or “things that make a good story.” Everything is contextual, depending on your audience, the message and mood you want to convey, how the work will be used, etc. It’s impossible to say something is required for every single situation. It’s not just the impracticality that’s a problem, though. The real issue is that such lists of “things maps must have” have their roots in a concept of cartography as a series of steps to follow or pieces to assemble, rather than a holistic art form or craft. Good maps are not made by following a simple mindless procedure or making sure you’ve ticked off all the boxes. That kind of attitude is how maps end up featured on this site. It’s also the only way machines can make maps at the moment, and it’s probably why they’re often so poorly done (see also this post I made on my other blog).

A list of requirements for how to make a good map is dangerous because it tempts beginners into shutting off their critical thinking and their creativity. Rather than consider why something should be done, or trying something new, they simply follow the list. I’ve seen it far too often in students. It also leads people to criticize and think narrowly about otherwise good maps because they don’t fit rigid expectations. Instead of a requirement list, I would say that the best we can do is simply give a list of things to think about when making a map, not things that must be done. To their credit, the GIS Lounge leads off their “Ten Things to Consider” piece with the caveat that these are simply suggestions, “a starting point of things to contemplate.”

Beyond the philosophical problems of actually having a list of required map elements, there are issues with the specific items on the list. Namely, not all maps actually need these elements. Let’s take them one at a time.

Title: Most maps do probably need titles, but it really depends on the context. Something sitting in the midst of a textbook page may have an explanatory caption, instead. A well-done legend often explains what the map is about as clearly and as quickly as a title, as well.

North Arrow: Most maps don’t need a north arrow. I honestly cannot fathom why they are so popular. Consider the following map:

From the US Census Bureau, via Wikimedia Commons

It has no north arrow. Most of us can recognize the United States, and we’re able to, say, determine that Texas is south of Minnesota. Even if we weren’t familiar with the area depicted, we’d probably assume north is toward the top (and, if it’s not, then a north arrow becomes a much more necessary element), as that’s the common convention we’ve learned. But what if you didn’t know this convention and honestly weren’t sure about which way was north? How would you possibly orient yourself? Well, you probably don’t need to. You’re probably not planning on navigating using this map and a compass. Many north arrows on maps aren’t telling you anything you actually need to know, or don’t already know. They’re just in the way.

Of course, worse than having a needless north arrow is an inaccurate one. Consider the Robinson Projection:

From Wikipedia

Dropping a north arrow onto this map would be misleading, because where north is varies based on where you are on the map. It’s not always straight up — sometimes it’s up and to the left, sometimes up and to the right, sometimes straight up. The angle of north varies on most map projections, including the one above. Far better than a north arrow in this case is to use a graticule — the grid of latitude and longitude lines, which shows a reader how the cardinal directions change across the map. But even this is not mandatory — a graticule, like a north arrow, is only useful if people really need to have some idea as to directions. Certainly this happens from time to time — if you’re teaching kindergartners where the continents are, then they probably need that information. But if you’re showing this to a tenured professor, they probably already know that New Zealand is east of Australia.

And I won’t even get in to the times I’ve seen students put north arrows on maps of the South Pole.

Scale: Again, most maps don’t need a scale, either. Will people reading your map really be comparing sizes or measuring distances?  Probably not. Again, this is partly a matter of your audience’s familiarity with the area depicted, but if I’m reading the map below, I really don’t care how far apart the states are:

Of course, the other issue is that, since all map projections necessarily distort, the scale of a map is different everywhere. Sometimes the changes are small enough that it’s not a problem, but a scale bar on a world map is going to be wrong most everywhere. It’s better to leave it off rather than to mislead.

Legend: Finally, many maps can do without legends. For a prime example, have a look again at a map I tackled last year:

The legend on this map is completely pointless. Better to write “Cairanne” next to the big red dot in France and trust that readers will figure it out. Map literacy is much like verbal literacy — people learn certain conventions, and we can rely upon most adult audiences to know these. We know that the red dots are cities, and that the words next to them are the city names. No one needs to tell us that at this age. It’s just a waste of our time and space, and potentially confusing (one can wonder if Cairanne is actually a city out in the Mediterranean). Legends aren’t needed to explain every little tiny symbol; just the ones that your audience won’t know.

As with everything that goes onto a map, conscious thought has to go into application of map elements. They should not be rote, or random. They should be employed with consideration of the map’s purpose and audience. That’s what design is — consciousness. It is misleading to say that legends or scales or other map elements are mandatory, and such statements will only lead to more bad maps. We must teach thoughtfulness and sound judgment, not obedience.

I’ve decided to consolidate the Worldwide Campaign to Eliminate Needless North Arrows and the International Crusade Against Useless Scale Bars into the Global Consortium for the Thoughtful Employment of Map Elements (GCTEME). If you would like to join, send a self-addressed, stamped envelope to the following address:

Daniel Huffman
c/o: University of Wisconsin Cartography Lab
550 North Park St.
Madison, WI 53706

I will send you back a letter of membership that looks very official and which will win you respect at NACIS. There are no membership requirements, nor are there actually any benefits. Or activities to speak of, except telling your friends about it.




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