Posts Tagged ‘misleading


Shuffling Michigan

It’s election season here in the United States, and as we all know, the combination of democracy and mapping yields one main thing: cartograms! Those entertaining maps in which states, counties, or whatever have been resized based on their electoral significance.

The folks at Decision Desk HQ ( have been making cartograms for the party primaries, breaking each state out by county (or town, in some cases). I’ve only rarely seen county cartograms, and I don’t think I’ve seen one for election results before, so it’s great that they’re taking this on. But their approach is troubling.


2016 Republican primary results for Michigan. Decision Desk HQ on the left, New York Times on the right.

Their approach is to resize each county by population (# of total votes would be good, but no good could come of remaking these on the fly as votes come in), and try to keep the overall shape of the state. Unfortunately, in so doing, they shuffle the counties around any old which way. The Lower Peninsula of Michigan has 68 counties in reality, the Upper Peninsula has 15. But Decision Desk HQ has shoved most of the counties into the Upper Peninsula, which now has 58, vs. 25 that remain in the Lower Peninsula.

This means that we can’t really see spatial patterns, which is sort of the point of having a map. Notice how, on the NYT map, the gold-colored counties that went for Cruz are mostly clustered in the west. The Decision Desk HQ map keeps some of them there (in yellow), but scatters the rest of that cluster around the Upper Peninsula. The two purple counties both went for Kasich, and Decision Desk HQ would have us think they are neighbors (which would be an interesting thing to note as far as spatial patterns go), but in fact they’re the two teal-colored counties on the NYT map that are on opposite sides of the state. The list goes on.

A table would be better than the Decision Desk HQ map. Right now it misleads readers. If you don’t know Michigan Geography, you will come away with incorrect understandings of which regions of the state went for which candidates.

Making cartograms is hard. It is absolutely possible to level a charge of “spatial patterns are distorted” against almost any of them in some way. But most good cartograms at least try to preserve the topology. Example:

Does this mess up some of the spatial distribution? Most certainly. But the effort is there to try and keep some of it. Most states continue to border their real-life neighbors, and lie in approximately the correct direction to each other. The South is still in the south. Keeping those relationships, as best as one can, is critical. It’s what makes these things more valuable than an alphabetical table of states/counties/etc.

I must admit that I originally praised the Decision Desk HQ maps when I saw them:


That’s me. I said those things.

That’s because they do look pretty cool. And because I had no idea that all the towns of New Hampshire were probably in the wrong place. But when Michigan’s turn came around, I could not ignore the mangling of my beloved home state. I’m sorry, NH: I didn’t know what they did to you.

One Nice Thing: For those of you unfamiliar (since I post here only about every 2–3 years), I try to say one nice thing about any map I criticize. Decision Desk HQ deserves praise for applying cartograms to state election data; I’ve not seen that before (though perhaps others have done so). Constructing all these county/town population cartograms is no easy task. And they didn’t use the awful-looking Gastner-Newman algorithm. Instead, they’ve got a nice clean style of their own, which would be great if it were just much more accurate. I think that’s entirely possible to do while keeping to their aesthetic.


A Couple of Extra Oceans

Today’s maps come to my attention via my colleague Sam Matthews, whom I hope to get to contribute to this blog someday. He alerted me to and the wealth of intriguing and often unfortunate cartographic specimens to be found there. They have lots of material worth discussing, but for now, I’m just going to pick out a couple to highlight a problem I’ve not talked about before. Let’s start with their map of world mineral resources.

via Click to visit.

Fairly innocuous-looking, to be sure. Tan land, blue water. Standard stuff. But if you look carefully, and you obsess about projections as I do, you’ll see that this map not only has blue water, but that it’s sitting on a blue background. That is to say, there is no distinction between the map and the background it’s drawn on. The color used on this map to mean “water” is also used for areas that are not a map. Here’s a hastily annotated copy to help explain:

A lot of people looking at this map are going to think that there’s a bunch of extra water on the planet that simply doesn’t exist. The Bering Strait between Alaska and Russia is only about 50 miles wide. Here, it looks like a huge expanse hundreds of miles across. And this map isn’t the worst of them. Here’s another one from the same site:

via Click to visit site.

This map has an entire extra ocean added at the top, a vast unnamed and unexplored expanse beyond the Arctic Ocean, somehow more north than the North Pole itself. It’s bizarre and unnecessary, and worse, it’s misleading. If you want to know why Americans have such poor knowledge of world geography, at least a fraction of the answer lies in the above, along with all of the other carelessly assembled maps that people end up learning from.

Both of these maps could be fixed by simply inserting a neatline. A neatline is a border, usually just a black line, that separates the map from the rest of the page. The lines I have drawn in my annotated examples above are neatlines, albeit approximated. In cases like this, neatlines are the difference between “map sitting on a blue background” and “map of an alternate dimension where there are extra oceans.”

I’m actually not a fan of neatlines — I think they’re frequently unnecessary, as I argue in a post on my other blog today. While these maps would be improved by adding a neatline, they could skip it entirely by just making the page background something other than the color of the water. A bold concept, but I’m willing to promote it. Imagine: a map with blue water and a white background.

I'm going to patent this!

This phantom ocean problem issue crops up a lot with maps made using projections that aren’t rectangular, like the venerable Robinson projection above, or the Winkel Tripel. These maps have curved edges, and I suppose that bothers people who want maps to fit inside rectangles. Maybe I’m missing something. Maybe they ran a focus group and found out that people hate non-rectangular maps, or that they cause seizures or something, and that we ought to add a few extra seas here and there to fill it out.

Like most maps featured here, I can’t entirely fathom what goes on in the mapmaker’s head that makes them think it’s alright to just make up some extra water. The slogan for is “We do magic to Maps.” Maybe this is what they mean.

Critical geographers, I’m sure, could have a field day with what such maps say about people. The idea here seems to be that the landforms on the map are data, and that the oceans are merely filler, no better than the background. And it’s true, we’re a pretty land-centered species, for obvious reasons. Bodies of water are often second-class citizens on many maps, thought of only as “not-land,” or “no data.” And phantom oceans, like the above, are probably the result.


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.


Texas Grows 70% Each Year

Welcome back, everyone, to Cartastrophe: The Blog with First-World Problems (as a reader rightly pointed out recently). Today’s effort comes to us from the folks at the Associated Press:

This choropleth appeared this morning accompanying a story I was reading online about the new population numbers out of the Census Bureau. Most of the map is unremarkable, but the legend is worth noting. According to the title on the legend, the colors indicate population growth, in thousands. But, the actual numbers in the legend are marked as percentages. It is probably unreasonable of me to believe that the population of Texas increased 20,000%, as that would put their current population somewhere above 4 billion people. I believe that these numbers are intended to be percentages, and that the title on the legend is simply incorrect. Perhaps this map was made by altering an existing product, and the author forgot to make some necessary changes.

The more subtle, and much more common, problem with the legend is the arrangement of the numbers. There’s an overlap to the data classes. If a state had 10% growth, does it go in the third class or the fourth? Better, I think, to add a decimal place to these numbers so that the separation is clear: 5.0-9.9, 10.0-14.9, etc. Gaps between classes make it plain which numbers go in which class. Alternately, a more complex solution is a redesign of the legend. It may be possible to visually clarify that the 5-10 class includes all numbers from 5 up until, but not including, 10. Here’s a mockup of something that comes to mind as a potential design solution:

That may or may not be too difficult for the average reader to interpret. It’s off the cuff, so I’m not entirely certain about its merits, but I do believe there are visual solutions to this problem as well as ones which rely on changing the numbers. The latter may be more clear, ultimately.

The colors for the choropleth are largely fine, but I think the various shades of blue are a bit too close to each other to easily match back to the legend. Reducing the classes by one, or by making the darkest blue even darker and stretching the color ramp out would help ease this.

One Nice Thing: I appreciate the author’s use of small boxes of color next to the state names in the northeast. The states get pretty small up there, and figuring out the color of Delaware can be challenging. With this solution, there are always legible swatches of color associated with each state.


The Vanishing Kingdom

Yesterday evening, I was having a conversation with one of my roommates about Beaver Island, which lay in the north of Lake Michigan. It’s a sizable chunk of land with some interesting history. It was, at one point in the 19th century, home to a kingdom inhabited by a breakaway Latter-Day Saints sect, until the US government facilitated the assassination of its eccentric ruler and the ejection of the Mormon settlers. While mentioning the island to my roommate, I pulled up Google Maps in order to show him where it is. Except it wasn’t there. An entire archipelago, in fact, was missing from the map. Compare the satellite photo to the map and note the difference:

Screenshots from Google Maps, 6/29/10

Perhaps more amusing is the fact that, when you zoom in sufficiently, the road network for Beaver Island (which has a population of about 650, according to Census estimates) still appears.

Screenshot from Google Maps, 6/29/10

Now, I don’t know how the sausage is made over at Google, but I’m guessing it’s a mostly automated process, given the magnitude of their undertaking. And this is what happens when you let computers keep running with insufficient oversight. This is not exactly a tiny island — it’s 55 square miles, and given how large of a scale Google lets you zoom in to, it’s not something that should be left off. Whatever algorithm they’ve used to generalize their data, it’s in need of tweaking. It’s leaving some smaller islands, but eliminating larger ones. Note the smaller Manitou Islands in the south of the first images above, marked as Sleeping Bear Dunes National Lakeshore. Despite being uninhabited and smaller than Beaver Island, they made it on the map. One of them is rather terribly distorted, however — the polygon is way too simplified for the scale.

It’s been said over and over again, but it’s still worth hearing: be careful when using Google Maps and its cousins. There are very few human hands in their creation, and not enough of the scrutiny required to prevent gaffes of this magnitude. Of course, you should be careful when using any map; once humans start making the data and design decisions rather than computers, major geographical errors may become infrequent, but more insidious problems crop up, as we discussed a few months ago.

This is also where learning lots of random geographic facts can be handy. It’s easier to catch the omission of Beaver Island if you know ahead of time that it exists. This is how I justify spending way too much time on Sporcle taking geography quizzes — it will hopefully make me less likely to make an error like the above.

The lessons from today’s map are obvious, but it’s always good to be reminded from time to time of the importance of careful editing. And the end result is a bit amusing here.

One Nice Thing: At least they’ve got a form on the page which I can use to report this error.

Tomorrow marks one year of blogging here on Cartastrophe. I really wasn’t sure that this experiment was going to last more than a few months, but your comments and emails and support have kept things lively. I appreciate your coming along for the ride. To all who have sent submissions: thank you. I don’t use all of them, but I appreciate everyone keeping an eye out and thinking of me, and hope you will keep doing so. This blog has been great for my own growth as a designer, and I hope that you have gained something from it, as well.

Finally, it comes to my attention that there’s another blog out there in a similar vein to my own. If you’d like a double dose of map critique, have a look at Misguided Maps.


Concerning the Value of Human Life

Today’s effort is brought to my attention by one of our readers, Robin, who previously alerted me to the problems of Moon Maps. This map appears in a post on the OKTrends blog, where the authors analyze the geographic distribution of how people answer various questions on the dating site OKCupid. We’ll take one of them as an example:


Obtained from Legend, title, and map combined by author into one PNG file.

Side note: the darkest red, for the highest percentage “No,” shows up as a single pixel at DC. So, I cannot claim that the map doesn’t follow the legend. Though, the DC dot is so unnoticeable it might as well not be. Putting an area on a map which is too small to be seen is a serious problem. Better for the authors to include an inset or two, showing the smaller states in a more magnified fashion (as we say in the business: at a larger scale).

There’s a fundamental error that a lot of people are prone to making with these maps (and, in fact, I didn’t notice myself doing it until I’d spent quite a while looking at these). If you look at the map above, or any of the others in the OKTrends post, there is always one state at each end of the scale. In the above example, Nevada is the brightest green, matching the far “Yes” end of the scale, and DC (thought you can scarcely see it) is the darkest red, matching the “No” end of the scale. This does not mean that 100% of the people in Nevada answered yes and 100% of those in DC said no. It just means that more people answered yes in Nevada than anywhere else. Maybe in DC 2% of the population said “yes,” and in Nevada 5% did, with all the other states in between. But this legend makes it appear as if DC uniformly said “No,” and Nevada “Yes,” with the vote being split in all other states. It is unintentionally misleading, which is the most tragic cartographic sin. The authors wanted to convey some information in good faith, but their communications became twisted and false.

The Yes-No labels on the legend are not the only problem. It’s the color scheme. It’s a diverging color scheme – the green and the red are opposite ends, and states shade toward one end or the other. There are many good reasons to use these schemes, but in this instance, it just makes it look like there are solid No states and solid Yes states, instead of states where a handful of people said yes, and those where a slightly larger handful of people said yes. The color scheme should be one hue, changing in lightness (say, from a pink to a dark red), and the map should show % yes votes (or % no) votes only. This still lets you pick out trends – Nevada has more Yes votes than other states, but it doesn’t mislead you in to a panic about the amoral citizens of Nevada and how they disregard human life. You can tell that “yes” is unpopular, but less so in certain areas.

Another reason to ditch the red-green scheme, which the authors use uniformly throughout their maps: It doesn’t always make sense when the options are other than yes and no. Here’s a map from later in their post:

Obtained from Legend, title, and map combined by author into one PNG file.

Obtained from Legend, title, and map combined by author into one PNG file.

These two colors, green and red, have certain connotations of positive and negative in much of the english-speaking world, so here, the scheme is a problem, unless you’re going with an implied value judgment where “Right to Bear Arms = Good” and “Right to Vote = Bad.” The people on the OKTrends blog don’t quite strike me as that type. Nor the type to greenlight an unequal valuation of human lives. And, of course, the legend does again make it look like Idaho is 100% behind giving up the right to vote. I’m guessing (and it is just guessing) that if you looked at the data, the vast majority of respondents in each state said they’d rather keep the vote and lose their guns. But Idaho happened to have the most people who were more fond of guns than voting (hard to hold that against them, given the political climate). Probably just a few percent. But people will come away from this map with the sentence stuck in their mind “Idaho strongly prefers to lose the right to vote.” I have belabored the point, so let’s move on.

Note that there are two states in the lower right corner which are not actually filled in with any color. Thanks for playing, Hawaii and Alaska! It’s OK — they’re just happy to be there, given how often they’re left off of US maps.

The shapes of the states are poorly generalized, and may in fact have been drawn freehand. Possibly just traced loosely, instead. But it has that feeling to it. Many of the states look slightly-to-moderately wrong. Look at my beloved Michigan – it’s become an amorphous blob. Saginaw Bay is entirely missing. It’s a sizable body of water. Like, nearly as big as some states. Also, I’m pretty sure Ohio doesn’t look quite like that. And Maryland seems to have taken over part of Virginia. Wyoming, though, is just as rectangular as ever.

I would be tempted to complain about the map projection, but since I think it’s freehanded, it doesn’t exactly have one.

Note the line around Michigan, showing the water border between the US and Canada as it passes through the Great Lakes. Except, the line only shows the border as it passes through two of the lakes. The actual border passes through two additional ones, north of Ohio, Pennsylvania, and New York – but you don’t see that section here for some reason. So, we have part of a Canadian border. And no Canada, by the by.

The map suffers from the dreaded island effect, where the US looks like it’s floating off in the ocean with no land nearby, and Canada looks like a great and forbidding sea, much like the Gulf of Mexico or the Atlantic Ocean. I might not call this a problem for this map otherwise, but putting a portion of the Canadian border in, and then not actually drawing Canada, makes this a serious issue.

Nitpicky: Both maps have a few artifacts here and there, like in Louisiana in the bottom map. A few pixels the wrong color.

One Nice Thing: It’s an unclassed choropleth, which I rather like. Most choropleth maps organize data into classes – say, one color will represent all states with yes votes between 0% and 5%, and the next color will be for states from 6% to 10%, etc. — the states are grouped. In an unclassed choropleth, such as those above, each state is given a color in exact proportion to the number of votes for one choice or the other. A state with 1.1% yes votes gets a different color from one with 1.2%, because they have different values. They’re never grouped together into the same color, as they would be in a classed choropleth. There’s a whole debate as to which is better, classed or unclassed, and I will not get into it here. I will just say that I am a fan of the unclassed choropleth, so I think it’s a Nice Thing.

Addendum: I am a bit embarrassed that I didn’t notice this at first, but these maps are very unkind to the millions of people with red-green colorblindness, as several commenters on the original OKTrends post mentioned. Here’s an approximation of what a red-green colorblind person sees when they look at one of these maps:

Run through with protanopia filter

Run through with protanopia filter

Designers cannot ignore such a vast population, and must take color vision anomalies into account.


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