Cartographic hyperbole

Just when you think we've exhausted mapping the 2016 Presidential election maps along comes another. New York Times' 'Extremely Detailed Map' presents precinct level data from the work undertaken by Ryne Rohla.

And thus, my Twitter feed went into a late night tail spin as I saw, in equal measure, exasperated cartographers bemoaning the map and political commentators and everyone else and their dog exclaiming it's sheer wonder. I offered a few comments which drew plenty of agreement, but which also had others telling me that the map wasn't made for master cartographers etc etc. No, Nate Cohn, the map is not 'as I've never seen it before'. It's not 'amazing' or 'Incredible'. No, James Fallows, the map is not 'great'. Such hyperbole simply reinforces people's beliefs because they take their lead from the sort of comments you make. Who cares what a few expert cartographers might have to say on the topic...you know, those people who are actually qualified and experienced in ways that make their perspective worthy.

So what's my beef? First off, the map is not 'wrong'. The data is more detailed than many others (including virtually all I made) by being at the precinct level and not the county, or state level. So you have smaller geographical areas. Detailed, yes. Accurate, certainly. Useful? Absolutely not because of the way the map was made. The very fact that it's made for a public not versed in cartographic wizardry is precisely why maps like this need strong cartographic editorial control. The general public is drawn in by the headline, they are told detail matters and they infer that the map must be bloody great because they are told it is.

It's a straight-up choropleth showing share of vote. Darker shades of red for a higher Republican share and Darker shades of blue for higher Democrat share. It uses a standard diverging colour scheme. Again, not fundamentally 'wrong' but the choice of map type and symbol type lead to a very particular map. A map that, visually, over-emphasizes geography.

You see, there are hundreds of small areas on the map with ridiculously low population counts which are given equal (and sometimes greater) visual prominence as other far more densely populated areas. An area that has 100 voters and 90 of them voted Republican is shown as dark red and a 90% share. Exactly the same symbol would be used for an area that has 100,000 voters, 90,000 of whom voted Republican. The differences between the number of people who live, work, and vote in each area is fundamental to the impact the resulting map has on our senses because we end up seeing a shit load of red. That much red distorts our perception of the result. It exaggerates the election results by persuading our eyes that more red equals more votes and a larger winning margin. That simply isn't true. Many small areas with a lot of people carry far more importance, electorally, than many large areas that have small population counts. And so, the map misleads, it reflects more of the geography of the country than it does of the people of the country. That huge swathe of red down the middle of the country is not a huge crowd of Trump voters, distributed as evenly as people on the two coasts, but simply where sparsely scattered people preferred Trump's pitch.

The very same data was far more eloquently mapped by The Washington Post back in September of 2017.

This map takes the very same data yet is designed to ameliorate the form. It considers the underlying problems of its distribution and the geographies it is bound by. It then reflects on how best to show the same data in a way that a person needs not to have a degree in cartography or electoral geography to disentangle the reality form the mapped form. In short, they thought about how to rid the map of misleading symbols and present a more truthful version. This, is good cartography. Where a cartographer has actively considered the impact of his or her design choices on the map, the message imbued in their choices, and the way the map will be perceived and cognitively processed.

The Washington Post map scales point symbols and uses subtle transparency shifts to take account of geographical and population distribution disparities. Same data. Fantastic map. Still plenty of red but, now, in visual balance with the rest of the map. And comparisons are what maps like this are all about. We see one place and we visually compare with another. That's how we assess our understanding of spatial patterns and the simple processing of where there is less compared with more.

Back to the NYT map for a moment because there are other problems that I honestly cannot believe we're still talking about. The map uses Web Mercator as its projection. This is flat out wrong for a map where you want, sorry, NEED, equal area to be maintained. Just dumping the map across a Web Mercator basemap is downright lazy. Alaska...

And the 3D view...holy crap map. It flips the map to an oblique angle but the map is flat. Flat as a bloody pancake. There's nothing 3D about it whatsoever. A gimmick. A pointless, and mis-labelled gimmick that ends up distorting the relative coverage of colour even more. Foreground gets visual prominence. Background recedes.

So there we have it, the latest election map. Not the best by any stretch but another clear demonstration of the vital role cartographers have in educating people to understand that what they are seeing is as much a function of the choices in map design (and laziness in not doing anything to prepare or display the data) than it is the actual data. Making maps for mass public consumption demands good cartography, not technical gimmicks. It demands you reflect on what the map will tell people through your design choices. Cartography mediates understanding. The lens of the map-maker is fundamental to how we see the world. If you choose, actively, or through ignorance, not to bother with cartography then your map is doing your viewers a huge disservice and reinforces the already pathetically poor appreciation of geography that exists in society. Think about it. Do better, and end the nonsensical cartographic hyperbole that this sort of map crap feeds.

I'll end with this...Nate Cohn trolling any and all of us who make comments on the problems of the default choropleth.

Let me be clear...I love a good choropleth map. Modify the map by adding in an alpha channel to visually mute areas with smaller populations and you've got a good choropleth. Put it on an Albers Equal Area projection and you've got a great choropleth. Alternatively, modify the geography to account for population and you've got any number of different cartograms all with choroplethic symbolisation. Do your due diligence and make the map right.

GIS maps

There's no such thing as GIS maps. GIS is a Geographical Information System (by the way, it's not a GIS system). It's also the acronym for Geographical Information Science. You can do a lot by combining GI Systems with GI Science. One function of which is to make maps. But they're not a special breed. They're just maps, much like you'd make a map using many other tools.

Making maps (part of cartography) has always been a combination of art, science and technology. Get that magic recipe right and you'll make a pretty good map. If any of the three pillars drops short on quality or because of your ability to control them then you'll likely end up with a substandard map. GIS, then, is a core technology that supports cartography. It also does a lot more through its multitude of geospatial functionality. Of course, many people make maps using GIS because it's a core output. The map communicates results of analysis, illustrates natural and human conditions and tells stories. There's many different mediums of map that a GIS can support - web, animated, 3D, print, atlas etc. These are the maps. They're not GIS maps.

I can't recall a time during my career when I ever called one of my maps a pen map, photo-mechanical map, scribed map, MS Paint map, Coreldraw map, Aldus Freehand map, Adobe Illustrator map, Flash map, Javascript map, Silverlight map, HTML map, GIS map et al.. Maps have always been made using different technologies. They continue to be made by different technologies. Your choice of tools is underpinned by multiple influences but you don't strive to make a GIS map. Hopefully you strive to harness the opportunities of your chosen tools and go beyond the defaults to make a map that cannot be defined by your tool of production. Of course, no map-making software is perfect and we all work within limitations but that's always been the case with any map design and production technology.

It's true that many maps made using GIS have a similar appearance but that's the fault of the person making them because they do not go beyond the defaults. It's why you can often spot a map made using GIS because the defaults can be like a fingerprint. If not modified, line weights, styles, colours and fonts all scream of your chosen map-making software. We therefore end up with what I think people mean when they refer to GIS maps - a data dump that lacks design and has common styling characteristics and a particular visual aesthetic. I'd simply call those crap maps rather than blame the software.

Defaults are a necessity in any mouse-driven maps (see what I did there?). They give people a starting point in the software and, over time, they really have improved tremendously. But you're still expected (advised?) to then apply some art and science to make something fit for purpose because, although defaults iterate and improve, it's pretty much impossible for a piece of software to know your precise requirements. Sure, sometimes a default is fine but becoming a smarter mapmaker demands that you critically evaluate what the software gave you and adjust if necessary.

All so-called GIS maps are not the same. I see plenty of pretty crap maps made by people using GIS. I also see some absolutely exquisite maps. I might also say the same about maps I see by people who use Illustrator or Javascript yet no-one pigeonholes those maps by their technology de choix. It therefore strikes me as a little unreasonable to paint maps made by GIS as a special case. A map is a map.

So, just a heads up - if you tell me you've made a GIS map I'll immediately think it's an ill-designed data dump. If you tell me you've made a stick chart for navigating the oceans then you've just made the exception to the rule because that genuinely is a chart made of sticks (ht to Craig Williams for that!). I guess hand-drawn maps might also be a special case though, of course, pretty much all maps are made by hand, mediated by particular instruments.

Warp Factor Eleven

The UK Onshore Geophysical Library's William Smith - Interactive has wound me up.  It represents a cartofail that's extremely common.

William Smith produced his classic and beautiful maps of the Geology of England and Wales in the early 1800s. They are stunning. making them available digitally is also wonderful but...and this drives me nuts - why oh why, time and time again do we see people scan these wonderful old maps and then warp them to Web Mercator?

There's a reason Smith chose the right projection for his maps....because it was the right projection.

Would it not be easier to just change the projection of the web map service you're using and then allow the maps to be seen as intended? Instead we get the maps stretched and distorted. Horizontal text also becomes stretched and sits on a curve. It looks absurd.

200 years ago Smith made his map right. The very least we can do is honour it by using modern technology to re-present his work properly, not turn the warp factor up to eleven.

The NYT election map

It's election time in the US. It has been for well over a year (which is madness in itself) but we're down to the wire now with only a week to go before polling in what must be one of the most hate-fueled, vitriolic contests ever. Lies and misinformation have taken centre-stage but the sad truth is there are people (people who vote) who are easily taken in by lies and misinformation. They are sold it as a version of the 'truth' they can relate to and in which they wholeheartedly believe. And so that's how propaganda becomes reality and how candidates gain disciples. It's often the same with maps because they too sell a version of the truth.

We're arguably on the cusp of something far more important than worrying about a map in a newspaper but to my mind, at least, today's HUGE map in the New York Times warrants some cartonerd attention.

In today's print NYT: the most detailed election map we've ever printed: 30,000+ zip codes across a 4-page spread. pic.twitter.com/yjUHNSEvU2

— NYT Graphics (@nytgraphics) November 1, 2016

It is a truly magnificent piece of work. Large format. Eye-catching. Detailed. The US is a big country so if you want to show 30,000+ zip codes you better make your map big. I am a huge admirer of the New York Times graphics team and their cartographic work but this map, I'm afraid, contributes to the misinformation that has become so toxic this election season. Let's not worry about the periphery because it's the main map that takes centre-stage. It's that image which is defining and the impression that people see.

So what do they see? RED...lots of red. Any map that attempts to summarise a sparsely populated data set into a surface that exhausts space will mislead. It's inevitable. And with the USA, with a very heterogenous population distribution and vast swathes of land with barely a single rattlesnake of voting age it's a problem that is accentuated. The map uses Zip Code Tabulation Areas instead of counties, voting precincts or other geographies. There are problems with how ZCTAs mis-shapes the view but, frankly, any arbitrary boundaries have the same problems - the Modifiable Areal Unit Problem - statistical (and ultimately visual) bias that results with how you aggregate data into areas. The geography is what it is...but rather than perpetuate visually incongruous issues it's beholden on map-makers to deal with it.

For the last few years in my day job I've given a workshop at the Esri International User Conference that takes a single dataset of the 2012 election results and explores a range of about 20 different ways to present the very same data - each of which tells a very different story. Some of the maps can clearly be used to portray a particular dimension of the result and some can be used in deplorable ways (pun intended). Some reveal detail. Some mask it. Some show red. Some blue. You can see the full range of maps here if you're interested. The point of the session is to open people's eyes to the inherent biases that maps contain. What surprises me year on year is that an audience of people heavily invested in geo are equally surprised at the problems we explore. I guess it's to be expected - not every geo-expert is going to be a cartographic expert and they come to the session to learn and that's a great thing. But they are merely a small fraction of the population. The vast majority have no access to this sort of education. More than that - they have no idea they might even benefit from it or that there's a problem with how they read the maps they are served.

It's really a much bigger problem of geographical illiteracy and the lack of the basic need to view maps and graphics critically. With all these much larger issues it therefore becomes crucial for media organisations and those involved in communicating information to be cognisant of the limitations of the consumer. It's not really their fault - we're all born that way and we have a natural tendency to believe what we see, especially if it comes from a so-called reputable, impartial source. Maps should portray reality in a way that deals with the biases people inevitably see - to counter them rather than feed them. You only have to read the comments in reply to the NYT tweet to see how the map has been viewed and interpreted.

The problem with this New York Times map is the country itself which, admittedly, there isn't much they can do about but they could deal with the problem using different maps.  The size of the areas used to summarise the data are unequal. Some are therefore more visually prominent than others. Republicans hold on to large swathes of centrally located territory. Democrats get a shed-load of votes from the smaller, peripheral northeast. Additionally, they contain very different numbers of people so population density is unequal across the map - yet in terms of the symbology, each area is treated the same.

So you end up with large swathes of sparsely populated large areas in the mid-west being seen prominently and very small, densely populated areas on the coasts being seen much less prominently. The problem is compounded by two other factors - colour and focus. Red for republican is a colour that is seen more brightly than blue for Democrat. It is cognitively processed as 'more important'. Our eyes also naturally tend towards the centre of an image and a map on first inspection - so that's our initial focus. this all adds up to one massively misleading picture of the political geography of the USA. It screams REPUBLICAN which given Trump's persistent comments about the corrupt media is either an attempt for NYT to redress the balance or the Russians are to blame. And yellow for the marginal areas? I understand the desire for a neutral colour but in a generally two-horse race (mule, elephant, whatever) adding in other colours paints a different picture as well.

It can be different as these following maps of the 2012 election results, mapped by county, show. Using a value-by-alpha approach that overlays a layer of population density that is symbolised so that sparsely populated areas are more opaque will modify the image. It tunes out sparsely populated areas and brings a little focus to the areas with more people (more voters). All that deep red on the NYT version has now gone. Focus is shifted.

A cartogram does a similar job but by changing the shape of the areas - either warping them in relation to population density (e.g. a population equalising cartogram) or by giving each unit area the same shape (e.g. a hexagon grid). Yes, these are abstract and there's sometimes a challenge understanding the geography but they deal with the problems.

There's even the simple, yet effective, proportional symbol map that often gets overlooked. Symbol overlaps are often hard to reconcile but the symbol sizes do a good job of showing where there is more and where there is less as well as encoding the different colours.

Finally in this small selection of the myriad of alternatives, a dasymetric technique which uses a secondary layer of data into which you can reapportion the data can also show a more accurate distribution of information (e.g. dasymetric dot density) though, of course, any map of population data presented in this way will take on a similar appearance because, well, that's where people live!

Ultimately, there are dozens of different ways that the map can be made. None are 'right' and none are 'wrong' but they all tell different versions of the truth. This isn't cartographic pedantry. It's an important issue because it plays to people's views, opinions and search for the truth. My point here, is that maps can be extremely dangerous graphic tools. The NYT have, in my opinion, contributed to the misinformation that has enveloped this election by publishing this map in the form they chose. It presents a version of the truth that suits a particular view of reality. It is biased and dangerous. It's also too late because it's out there now and is simply just another piece of rhetoric people can use to support their own version of the facts.

By the way, I don't get to vote in the US election but I have lived and worked in the US for 5 years and call it home. Please...do yourselves a favour and go vote. You only have to look at what happened in the UK a few months ago where the vote was to leave Europe...a vote massively impacted because many people failed to turn out to vote who would otherwise have voted not to leave. You can't vote by liking or re-tweeting. Whatever the map says to you...just go and vote and help redraw the one you want.

UPDATE: Since writing this less than an hour ago the Washington Post has published a very well-timed piece entitled Election maps are telling you big lies about small things. They've been advocating cartograms based on one area per electoral college vote which I like. It retains a State-based appearance (which isn't as difficult to read as the population equalising versions) while doing a good job of presenting a visually balanced view of the data. I encourage you to read.

UPDATE 2: And now a good review of past approaches from NYT here. A rebuttal of the criticism they've faced? Maybe. They try and frame the big map as an attempt to look at the way physical geography impacts political patterns. That's a very nuanced way to explore the distribution of voting and I'd still argue that most who read the map will take away one message...more red = more Republican. Seven days out from the election is not the time to be playing with people's inherent perceptual and cognitive bias.

Cartographic Cost of Open

The recent retirement of Kobe Bryant of the LA Lakers had the LA Times reveal a beautiful map of every shot he ever took - all 30,699 of them. It's a lovely piece of large scale mapping that sits at the intersecton of data art and information graphics. You really should see the live interactive map here because the screengrab below doesn't do it justice. That said, I'm sure you'll already have seen it. The LA Times also gave us a great 'how did we do it'.

My good friend Mike Gould this morning posted this:

I wonder just how many times cool visualization a.k.a mapping of NYC taxi routes and basketball/tennis shots data can be reinvented

— michael GOULD (@0mgould) April 22, 2016

My thoughts on this congealed over breakfast, spurred on by a twitter conversation I followed in the wake of the LA Times map on Bryant's shots. Mike's right in many respects - he's alluding to the idea that it's getting a little tedious seeing so many so-called re-inventions of maps.

You see, this sort of shot chart/map has been done before, most notably by Kirk Goldsberry who also mapped Bryant's shots back in 2013.

Plotting data points on a map is not a new phenomena that began with Kobe Bryant shot data but a few people pointed out the similarity between the LA Times version and Goldsberry's. There's no getting away from the fact they do look similar but - same dataset (although LA Times is more up-to-date), same court structure (hard to get away from though LA Times flipped the court) and same colours...well, any self respecting map-maker would inevitably use the Lakers' purple and gold colour scheme in their overall design.

So what? To my mind there's no copyright or Intellectual Property Right on a mapping technique. Yes, there's a lot of copyright associated with cartographic brands - because the style of a map or a map series often goes hand-in-hand with a long-term objective for brand recognition. Think of any major mapping agency such as SwissTopo, National Geographic, Ordnance Survey. Think London Underground. Think New York Times graphics. They are all very protective of their brand which is really just a function of the very particular style they have designed and honed over many years. Yet many other people use the same mapping data and make maps of the same places that all these mapping organisations do. That's what's happened in this era of open data. Mapping data has become democratised, often emancipated and made available to everyone, not just the big cartographic and media guns. Further, data feeds and all sorts of interesting datasets (like basketball shots by individual) are made available for free or at low cost. It brings tremendous access to the data and inevitably, a clamor to map it. It's therefore inevitable that similar designs will emerge.

But c'mon - the fact that one person makes a map of the data and then someone else does really shouldn't get people so upset because you can't have it both ways. All this free and open data does not come with a disclaimer that:

1. If you are the first to make a map with it you win and no-one else can
2. If you settle on a design that riffs off others then sure, give them a nod, but it's not obligatory


Importantly, you should probably be aware that you probably weren't the first anyway. The same thing has happened with the NYC taxi cab data. There are plenty of people doing very similar things. That's the cartographic price of open. We're getting a lot of maps shouting and competing for attention, all clamoring to be seen as original, distinct and the best.

This presents real tensions. I often get asked if you can create a particular map using Esri software and the answer is almost always yes BUT...and it's a big but...if another mapping company has an example of that type or style already (or someone who is a proponent of an alternative mapping platform has made one) then if I go and make one that looks similar guess who gets slated? For instance - making stacked chips on a map is neither new or difficult. Erwin Raisz was doing it by hand in the mid 1900s for example. I had a good friend make one in our University project atlass in 1991. If I go and make one now I don't get accused of copying Raisz...I get accused of copying a more recent viral version. This mindset of attributing originality and intellectual property to only recent versions of techniques is baffling and damaging. The fact you can use any number of different pieces of software to deploy a particular mapping technique is a good thing but please don't see that technique as belonging to one person or organisation over another.

I've had similar experiences in the past and, again, recently. I'd been playing with the Mars MOLA elevation data as a bit of a side project and then Chris Wesson drops his very elegant map - in the style of an Ordnance Survey map sheet. Now, Chris works at Ordnance Survey so he's entitled to use that design and it's an interesting take on how to process the data. Then Eleanor Lutz published a lovely hand-drawn map of part of Mars herself. And what of my map of Mars? - well, was I relegated to the third person to get their Mars map out? It depends when your starting point is.

Maps of Mars have been made ever since Giovanni Schiaparelli had a go in 1880. USGS has been publishing topographic maps of Mars for decades. Do a quick Google search for maps of Mars and you'll see that neither Chris, Eleanor or myself were the first though, to be fair, none of us has claimed to be. We just used the same data, did something different and hey presto - three more maps of Mars.

The crux is that if the data exists, people will map it. We really should stop being so precious about one map over another because if truth be told, pretty much nothing is actually that original any more. It's true that some maps bubble up and become internet stars and they are often seen as the version that people see as definitive. But it doesn't and shouldn't stop people from using the same data and even using some of the same ideas. Let me be clear - blatant rip-offs do exist and should be pointed out as such but there's often a fine line as I personally feel the LA Times map illustrates. Organisations and individuals have also developed very specific styles and these too should be seen as something worth protecting. But why would LA Times use triangles for the symbols and colour them in red? Makes no sense. It'd make a crap map. As long as they use circles and purple they run the risk of getting accused of some level of plagiarism.

Cartographic techniques are not copyrighted. I never see anyone reference Baron Pierre Charles Dupin in the footnotes of their choropleth maps, or countless weather map organisations as inspiration for the hideous rainbow colour palettes that seem to have become de facto in mapping weather. So - the LA Times need not reference Goldsberry's work or, indeed, John Snow as an early example of mapping discrete events in space using single symbols to see a pattern emerge (and that's not including the use of dots in demographic mapping going back to the early 1800s).

My point...open data has brought a wealth of new maps to the canon. They build off the legacy of many that have gone before but hardly any are truly unique. If we are happy to support the notion that we want open data and open access to data we have to also be happy with the notion that cartographic techniques and their use are also open...open to use and (as we often see), open to abuse.

Now go and search Google for Kobe Bryant shot charts...you'll see plenty more and also a load of hex-binned versions and so-called heat maps to boot. That's another story.

Finally - just a heads up...If I can find time, I'm going to try and make a map of some aspect of England's 1966 World Cup win as it's the 50th anniversary in July this year. I'm quite sure no-one else knows of this and no-one will either be thinking of making a map or of using the same data.

Kindergarten Kartography

Over the years I’ve seen many changes in learning in the realm of cartography. I’m going to use this blog post to reflect on those changes and offer some thoughts on the current state of education in cartography as I see it or, more specifically, how it's become monopolized by people with very little cartographic education of their own to speak of.

Many of us in the geo or cartography business, whatever we do, can point to a love of maps in our school-age years. Struggling for motivation to do something else, I took my own love of maps to what I saw as a more serious step by taking a formal qualification when I studied it for a Bachelor’s degree. I had in mind that I wanted to be involved with maps as a career of some sort and getting an education in them was a key component to becoming proficient and, well, qualified!

My degree course was a very vocationally designed course because it had served as an entry point to the UK cartographic industry for decades. A lot of it was practical but the practical techniques were nothing without the theoretical and conceptual understanding we were taught alongside. Of course, history now shows that many of the techniques I learnt (scribing, photo-mechanical production etc) are long gone and if truth were told, the course was probably lagging behind the technology at the time as computers were replacing many functions of the cartographic process. This is a fairly typical scenario as University courses still struggle to keep pace with the rapid evolution of technology.

As I graduated, the UK cartographic industry was rapidly shrinking as GIS exploded onto the landscape. But while the technology has changed profoundly, many of those key ideas, concepts, theories and abilities to critically evaluate have changed very little. The technical and practical aspects were quite honestly the most trivial aspect of my degree. It was the thinking and the development of a cartographic mind that was the most important aspect. Of course, at the time we though just making a decent looking map would get us a good grade. Often that was the case but rarely did we really appreciate that our tutors were actually grading what was going on behind the map…not what the end product looked like. I used to use a pen and scribing tool. I have coded maps before and now I work with servers and portals and other ‘stuff’….increasing animations and 3D. Anyway, the point is, we can easily pick up new ways of doing but picking up the thinking behind the doing isn’t a trivial learning task.

So I loved maps and wanted to better understand them and how they were made. But more than that – I wanted to prepare myself for entering the workforce doing something I loved. And in deciding upon that, the logical step is to do your research and find out where and who is going to give you the best education. I was going to go to Swansea University to do their Topographic Science degree but I ended up going to Oxford Polytechnic. Like most people looking for higher education, University was a logical step. I wanted to learn from the best; people who had been there and done it and who had their own qualifications as badges of authority and experience in cartography. My tutors were internationally known and contributed to cartography in academic and industrial settings. I went to arguably the top place for budding cartographers because I wanted a high quality education and to join the pantheon of cartographers who could point to their alma mater as a badge of quality. The best I could get from masters in the area to set my career up in the best way I could.

As I entered an academic career I soon began learning how to teach and how to be a researcher. Pedagogy became a very important component of my professional life. I had learnt domain knowledge during my degree studies and the mindset of lifelong learning means that I still learn every day. I had practical ability yet the practice of cartography was already rapidly changing and I never used photomechanical production techniques in a real workplace. As an academic I probably wasn’t as practiced as I could have been (a common accusation of teachers generally) but the skills and techniques of being able to teach and lecture were vitally important. I took courses in pedagogic theory and various diplomas. Over the next 20 or so years the process of lifelong learning you acquire as a professional academic meant I kept abreast of current thinking to inform my domain knowledge, my practical abilities and changes in pedagogy. You never become a finished article either in domain knowledge or the ability to teach but knowing how to question and, importantly, to find out the bits you don’t know is important. You also learn an awful lot about people and how to help, encourage or push people to achieve their own goals. Teaching has its very own set of vitally important skills over and above the content.

So where’s this going?

Ultimately, I left academia because I was tired of the admin and bureaucracy. I really enjoyed teaching my students and helping them realize their own passion in mapping. Sometimes I’d lose some along the way because they actually weren’t that interested. Some now have very successful careers in geo and that makes me proud. Some teach…some teach cartography. I stay in touch with many of them. During my academic life I went to many conferences and I could be absolutely certain each would have a panel or a discussion on pedagogic approaches to teaching geography/cartography/GIS/whatever. The format was largely the same. Often it was the same people. The outcomes were normally the same…largely boring summaries of the need for more…better…free…blah blah blah yackity schmackity. Alongside this in the literature, debates raged about the fashion for degrees that were focused on theory to become more vocational and vice versa. The training vs teaching argument was well worn. With heavily practical disciplines like GIS (whether it was ever a discipline at all was another debate entirely) should we be teaching concepts? Should people always have to learn using ArcGIS? Was a broad spectrum of software important to know? Were courses simply driving schools for buttonology? The debates were endless but one thing that characterized them was that rarely did people start from the last end point or argument. They just started again rather than consider the wider context. Their own narrow empire was their only concern. They did one thing very well and that became their very own ivory tower – the pinnacle of knowledge and learning for others to find and believe in.

Towards the end of my time at Kingston University myself and colleagues were well travelled, often leading sessions for other lecturers and academics in the UK on how to teach GIS, or cartography, or mobile mapping fieldwork. We were seen as leading in both discipline, practice and pedagogy. We received numerous research grants for developing technical innovations. We were researching and mapping social media feeds and taking advantage of them in teaching and learning nearly 10 years ago and helping others devise their own approaches for instance.

So have things changed?

The mapping landscape has changed profoundly. New software. New companies or organisations. Free and open data and software. Everything is quicker with social media feeding an endless daily appetite for something, anything, that people consume as ‘new’ (which often isn’t but that’s also a different tale). One person does x, the next responds with y. One person colours their OpenStreetmap in one fashionable way, another makes a hand-drawn version and yet another still does some crazy psychedelic trippy animated thing. All fun in the kiddie’s sandpit but what about outside the sandpit where the real world of mapping exists; where making a version of a basemap in an arty style actually doesn’t cut it for any practical purpose?

Things haven’t really changed and so the disconnect between theory, practice and praxis widens. I’ve seen panel discussions at recent conferences that have opened up the same tired debates, just with different people ignoring what’s gone before. We’ve largely solved the pedagogic debates about training vs teaching. It’s out there (in the literature) if one cares to find it but of course it totally destroys people who want to be seen as innovators to not be seen to be carefully considering this stuff. The discussions are repetitive and say more about the naivety of the panelists rather than their depth of understanding of either their chosen domain or pedagogy. They love playing in the sandpit but the tantrums start as soon as someone wants to play more seriously.

What I have observed is that the players involved are very different to those of 10, 20, 30 and more years ago in terms of the cartographic domain. Cartography seems to have become a past-time rather than either an academic subject or a professional vocation. Many involved in making maps are doing so from a background of education in anything but cartography yet they’re found a passion for making maps. They want to be seen as makers and doers and that is sufficient. Most of this is due to the burgeoning availability of data and the internet as a powerful democratizing tool. Cartographic technology has shifted so rapidly that it’s hard to conceive of someone now wanting to take a Bachelors degree in it. It doesn’t conjure up the image of a real subject any more. It’s been demoted to what a hacker might do with a couple of spare hours and a Mac Book in Starbucks.

So what courses do people want to study to gain qualifications in? It’s pretty much anything but cartography because you can now get your cartography from the internet or from meet-ups or from anywhere but an institution which is set up to deliver education. But the craziness of this situation is that many people who now purport to be fine purveyors of map education sought expert tuition for their own non-cartographic qualifications at some point. Yet now, they’re shouting loudly about how they are now best-placed to offer cartographic training. Let’s be clear – I’m happy for anyone to offer advice and training and help in areas they have some level of knowledge or expertise in but there’s no substitute to learning from experts – people who are experienced, have deep domain knowledge and have played beyond the sand pit. The mantra of beginners for beginners doesn’t cut it. Students in a Bachelors class being taught by an intern or teaching assistant is no substitute for the Professor. They have the merit and background to support and lead learning. They can assess the quality of work against expected norms and relative work. Not everything is super cool or awesome. Some work is, frankly, awful and you’re doing people an injustice by telling them simply by taking part you are becoming proficient or an expert in either domain knowledge or practical ability. As a lecturer I was happy giving fail grades. I was also happy giving grades well into the 90% and higher range. The variation was huge. Not everyone excelled. Some had natural talent, some worked hard to achieve. Grades reflected ability and outcome. I was only able to understand how to assess and comment on quality because I knew my subject and knew how to support teaching and learning through an understanding of pedagogy. By all means go and enjoy the colouring in with computers at a local meet-up and figure out a little trick that makes a task easier – but do not be fooled into thinking this equates to expertise.

And how did this dumbing down of cartographic education and the rise of kindergarten kartography come about? Because of the admin and bureaucracy I so hated. The documents, forms and paperwork that we had to complete to get a new or revised course up and running were horrific. We had to get industrial reviews. We had to pass the work across many other academic and practitioner’s desks. We had term reviews, semester reviews, annual reviews, quinquennial reviews and validation and re-validation events at which external people would pour over ever small item of our plans to check it and assure themselves of the standards it sets. That’s how proper education works. Checking and cross-checking and review after review after review. That was how, ultimately, we could stand in front of students and know we were delivering top class content in a modern, stimulating, caring and professional environment. All of that developmental work gave assurances to the student too. When we could claim most graduates got jobs in the field on graduation we were not making vacuous statements. We knew what we were delivering was what industry and society wanted and needed. We had their buy-in. We were meeting government-set targets for qualified and able graduates. We also kept pace with developments to ensure students were at least on the curve if not as much ahead of it as we could make it. Proper education leading to proper qualifications that were the student’s license to demonstrate they had a proper qualification in the subject they studied. A subject that had an avowed intent to marry domain knowledge with practical skills; to develop knowledge and understanding; a critical and evaluative approach; and a desire for lifelong learning. But too many people have become fed up with this requirement as they search for a quick fix. Taking time to learn something is not seen as a requirement for becoming an expert. Playing the long game is no longer regarded by many as a wholesome approach to learning and by many of the current crop of people who claim to offer educational or training services they do so based on a complete lack of quality assurance that anyone can rely on.

This is why I find today’s trend for short-form online learning and meet-ups as being heralded as THE place to learn cartography so dispiriting. Many of these people seem unaware of so much both in domain knowledge and pedagogy. They’ve rarely gone through any education or training in cartography so their badges are from other disciplines yet they now claim to be the carto-educators of choice. Frankly it’s a tough job to counter that culture precisely because so many formal courses are no longer offered but it doesn’t make it right. It simply doesn’t stack up. You can’t want a qualification from one set of experts then profess to others you’re one in some other subject. MOOCs, I feel, are a special case and most people seem to avoid the reality that many are done as loss-leaders to whet people’s appetite and get them sufficiently interested to take a fee-paying version of the course. Universities do it. Corporations do it. You hardly see any reading lists any more either – the ability to use Google seems to be the only requirement for an inquisitive mind. If content isn’t already online then it’s all too often seen as irrelevant.

Of course, much of this has to do with the death of cartography in the classroom. It’s inevitable people seek education from people offering it and if the traditional arena has dried up then of course motivated individuals and groups will see a gap in the market they feel they can fill. And I am part of that problem because I’d had enough of University life and the crap that got in the way. But I also hope that reaching an audience through various blogs and by continuing to go to conferences and meetings helps others. I’m also writing a book…yes, a real, live book to support much more than the return to button-pushing that current quasi-carto-educators seem to have returned to (side-note…you know, coding is also just button pushing by a different form. I don’t care whether you change the colour of a highway using CSS, javascript or a GUI). And, of course, people love ‘free’ and so free meetups with free content led by people who don’t charge for their time and where free pizza or beer is offered as enticement are bound to be a win win. Except what many don’t seem to realize is it’s a false economy. My suggestion is do some research and ask around. If you want to know something about cartography and really want to get an education in it, seek out a professional who has a background domain and pedagogic knowledge. In the UK I’d look at UCL, City University, Leicester or Nottingham University. In the US, just go check out Penn State, University of Madison-Wisconsin or Oregon State University. Of course, others exist but I’m just picking out a few places to start. Get your qualifications from relevant experts and not from the market stall purveyors who are offering knock-off merchandise. It might look like a good deal but it’ll probably break after a week or two. Get your background in cartography and don’t see Kindergarten Kartography as a sufficient substitute.

As a final thought I do want to be absolutely clear that I'm happy for everyone to have a go at making maps as I have said numerous times before. I'm also more than happy for people to pass on tips, tricks and nuggets of advice via many different forms. I use this sort of advice and self-learning ever day to supplement what I know and to learn from others. Don't mistake this discussion as some sort of claim that no-one is allowed to utter anything about cartography unless they've put in 40 years and have multiple badges of honour. That would be absurd. There is a place for everyone to contribute to the wider realm of cartographic understanding. It's just that the balance has gone. I feel we've tipped into a dangerous area where people are getting hooked on relatively appealing and accessible fayre masquerading as quality assured content. Get hooked on the good stuff and you'll find it sustains you much further than the local sand pit.

And by the way, next time you're at a conference watching a panel discussion on the topic of Cartographic education just step back and think about whether the panelists really have the chops.

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?

STATEMENTS ON CARTOGRAPHIC DESIGN

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.

THE 5 PRINCIPLES OF MAP DESIGN

1.  CONCEPT BEFORE COMPILATION
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.

2.  HIERARCHY WITH HARMONY
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.

3.  SIMPLICITY FROM SACRIFICE
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).

4.  CLUTTER TO CLARITY
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.

5.  EMOTION EXPRESSES, ENGAGES AND ELUCIDATES
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 am...in 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.

True Size of Africa - now in three dee!

A few years back, designer Kai Krause made his multi-viral 'True Size of Africa' graphic. It's what got me riled enough to start this blog and it was the focus of my first post as I re-drew the map using shapes from an appropriate equal area projection. I got called a 'marauding cartonerd' for making some salient observations and making the corrections.

He got a bit miffed that people were pointing out errors in his work but he remained committed to the cause of simply trying to show that Africa is a big place. His wholly misleading map constantly bubbles up on the internet. The critiques get largely ignored because few care about accuracy and the world keeps turning. Except he's only gone and updated the graphic.

Scientific American published his new graphic in a blog entitled Africa Dwarfs China, Europe and the U.S. in a section called Graphic Science.

Nervously, I went over and took a look...and this is what I saw:

Now let's be clear, the aim of educating people that the Mercator projection distorts our perception of reality and that Africa as a continent has suffered more than most is commendable. Fighting immappancy (as Krause described this lack of understanding of geography) is also close to my heart. But using maps incorrectly is where I get all cartonerdy.

You'd think, perhaps, that Krause might have taken some of the criticism on the chin and used this update as a way to correct his own immappancy. You'd also think that in a publication that profers the importance of 'science' that accuracy might be important. You also may presume that anything in the 'Graphic Science' section would be scientifically accurate in its visual display. Let's see eh?

Like many, Krause has embraced 3D. People love 3D. It looks cool and literally gives maps depth. So this new graphic is attention grabbing because of it's three dee-iness alone.

However - 3D blocks in perspective wrapped round a globe creates visual distortions. In just the same way that on a flat map that uses Mercator the north and south are distorted relative to the equator, on a virtual globe we see distortions in the relative size and shape of features as they move away from the viewing point - the point closest to us as map readers. China therefore appears predominant and his rendering of Western Europe starts to diminish as it begins to wrap around the curve of the globe. So, visually, comparing like for like from a single point of view on a 3D perspective drawing (or globe) isn't a good way of showing comparisons...particularly when it's based on the relative size of areas (I wrote of these issues in a separate blog).

Notwithstanding the visual problems with interpreting the relative size of shapes across a curved surface, if Krause has at least got all his shapes in proportion during the construction of the graphic then we might at least be able to assume some semblance of relative size. BUT...the sizes and shapes didn't quite look right to me so I popped open my GIS package of choice and played with some shapes.

Given I re-drew the original 2D version I thought it only natural to re-draw the 3D version so here's my attempt at re-making his map with the same countries on a virtual globe:

I had difficulties re-making his map like-for-like for the simple reason that the real world shapes are not the same as he presents. Here's where Krause's map seems to fail:

• China is not the same shape and has been warped to fit neatly over Madagascar.
• The contiguous United States is much larger than he presents.
• Krause included Germany and a partial set of Eastern European countries. There simply isn't room.
• The real India is larger than Krause represents.

Of course I'm being cartographically pedantic again but if the very thing you purport to show is misrepresenting reality I don't think artistic license is a sufficiently good excuse. Yes, you could argue it's only a little bit wrong but if you're going to do something, why not do it right? Few who look at the new graphic will even think to question its authority and they will glean a distorted picture. That's the real issue.

The world will likely jump on his graphic and proclaim it as a great way to visualize differences in the size of areas. Like his 2D attempt, it's inaccurate. Will anyone care? I do. Should I have made a 3D version? Probably not. The 2D version is far more useful at supporting visual comparison of areas. Adding perspective and extruding the shapes to volumetric blocks just adds unnecessary visual noise that creates problems for our human processing of the map's message.

ht to @cartocalypse for the link

Bend it like Mercator

After their win in the Champions League final yesterday, the 101 Great Goals blog published a piece on the relative location of FC Barcelona's triumvirate of South American strikers. They picked up a map from Reddit that showed their birthplaces as being positioned in such a way that you can draw a perfectly straight line between them on Google Maps.

Here's the map:

A headline writer's dream...arguably the three best strikers in the world all born in formation as well as playing in formation for the world's best team. An easy map to make...take a pen and draw a line across the map to link three red symbols, each of which is about 50 miles in diameter in real world units. Job done.

Except the map is incorrect...which makes the headline potentially incorrect too. A straight line between two places on the globe becomes a curved line when projected using Web Mercator (which the Google Map used by the author is in this case). You cannot simply draw a straight line on the map and infer that it represents a straight line on the curved surface of the globe - because it doesn't.

Here's what the line looks like on a virtual globe as if looking from Messi's birthplace to Neymar's birthplace:

And when we place that line back onto a projected flat map, here's the outcome:

The line now has a slight curve to it but with symbols about 10 miles in diameter it still just nicks the edge of the town where Suarez was born. If I'd used smaller symbols I could have shown the line doesn't pass through Salto, Uruguay. If I'd used big red blobs like the original then of course the line would pass through Salto. Built correctly, we not only get an accurate map...but one that supports the story even better!

OK, we're talking small margins here but the author of the original map got very lucky simply because of the quirk of geography relating to the three players he chose to link on the map. Because the three locations are relatively close to one another (in global terms) and they are also only 30 degrees or so south of the equator we don't see a massive distortion in the line. It has a curve, yes...but only a slight one.

But what if we look at three other footballers? Wayne Rooney was born in Croxteth, Liverpool. Harry Kewell in a Sydney suburb in Australia; and C. V. Pappachan, the famous (?) former Indian footballer born in Thrissur. Here's their map:

As far as I know there is nothing at all to link these three footballers but if we'd taken the mapping approach used to link Barcelona's strikers we'd also get a perfect straight line passing from Liverpool in the UK, all the way to Sydney, Australia via Thrissur on the southern tip of India.

If you got in a plane and flew the straight line route between the UK and Sydney the closest you get to Thrissur is about 2,500 miles. The red line shows the planar version of a straight line projected on Web Mercator. I included the Barcelona striker's line for scale which shows that smaller distances, particularly near the equator, 'appear' less curvier.

News aggregators, blogs and, well, pretty much anyone should question maps. They lie. They are terrible at telling porkies. Worse. Most map readers don't know they're being fed a lie because they look authoritative; and they don't know that the maker of the map they're looking at didn't know the pitfalls of their approach either.

As it turns out, Barça's strikers do happen to have been born close enough to almost lie in a straight line on the globe and on the map. The curve on the projected map tells the accurate story. Try telling the story using three other footballers who appear to have been born along a straight line on a map and chances are, they weren't.

Hat Tip to Brian Timoney for the tweet about this map.

Drug crazed mapping

I had told myself I wasn't going to bite when @Amazing_maps screamed once more for my attention. But the more I tried to ignore, the more it reeled me in so eventually I thought it worth a few comments.

Here's the so-called amazing map:

I've no idea who made it. It doesn't really matter. What I feel matters is the impact maps like this have on those that view it. This is more about the consumption of maps but, of course, their design and construction goes a long way to underpinning the message people take away.

Quick look and take away: Holy drug barons Batman,...San Bernardino is full of crack-heads! So are a few smaller areas I don't even know....but they're really small so they can't be as important eh? Right, must be time for Alaska State Troopers, turn on the TV...

That's how a lot of people will look at this map. Message delivered. Warped view of reality perpetuated. Job done. Wait for the next Amazing Map.

Here's the longer look and take aways I formulated...

Hmm. Something's not quite right with this map. Let's talk it through. It's a choropleth. We can assume from the title...well, the line that doubles as the legend title, what the subject matter is. It's about the labs, not the population so it's about production, not consumption. And the colour scheme goes from light to dark so we see where there are more meth labs and where there are fewer. I'll not repeat myself like a cracked record about it being totals (but it is) and not normalised (but it isn't) suffice to say it needs to have the data transformed into per capita or something equally sensible to allow us to compare like for like. Though critical for a choropleth, let's ignore that for the purposes of this because there's other 'take aways' in this map.

Look at San Bernardino County again...jeesz, it's heaving with meth labs.

This makes me a little more interested (perhaps concerned) as it's where I live. Notwithstanding it's totals, look at that large, expansive area filled with loads of meth labs. How many?...there's about...errr, well, let me look at the legend. hmm. It's dark blue. Does that make it 300, 500, 1000 meth labs?

It's impossible to tell without doing some assessment of the actual RGB values. It's actually closest to the RGB value about 1/3 along the legend colour ramp which would make it about 330ish...though there are no RGB values in the legend that match those found in San Bernardino County so it's impossible to be certain and why am I having to do an RGB analysis of a legend anyway? It shouts out from the map yet is nearer the lower end of the legend. That doesn't seem right.

So San Bernardino leaps out because 1. it's the largest county in the US 2. It has a lot of meth labs (though possibly not per capita or in relation to counties with many more) and 3. It's dark blue and that means 'more' except there's virtually no differentiation between the blue used at 330 and that for 1000. All the variation in colour value is at the lower end.

The map uses an unclassified choropleth approach. That means every data value is given its own position along the chosen colour ramp. I'm not a huge fan of unclassified choropleths. Choropleths are generally used to show where places are similar and that relies on classifying your data into groups that display similar characteristics. All you can really see from an unclassed choropleth is the extremities...which areas tend to the maximum and which to the minimum. It's really difficult to assess where those in-between values might sit...and that's assuming the scale is linear and the colour scheme is applied linearly. Of course, you can stretch colour to be applied non-linearly but then it's an even more confusing picture that's arguably more difficult interpret visually. If you don't classify data before mapping it then you're painting by numbers and it's a bypass to considering your data and teasing out the message through careful classification and symbolisation.

I'm going to add a caveat here - if the map is for interactive web display and the user can hover or click an area to retrieve the value directly, then unclassed choropleths are, arguably, less problematic because people can retrieve values across the map. I'd still contend, however, that if we know the map is classified into, say 5 classes using natural breaks then every county symbolized in the same shade of blue is 'similar'. It's an important metric we can easily see in the map and it's a good default. Other classification schemes exist to suit alternative purposes. If we use, say, a quantile scheme of 5 classes then we know each class shows 20% of the data values in rank order - again, similarity between values, across the entire range values, can be easily seen and it's simple to see which areas are in the top 20% of values.  If you make two choropleths then using something like a quantile scheme allows you to compare the two maps on a comparable cognitive basis. Clicking to retrieve a value is an additional step in the map reading process. Trying to remember values from one hovered-over area to another is equally taxing because our short term recall is not our best cognitive function (think of memorizing and recalling a pack of cards in order...it's not easy!). I like maps to 'show and tell' rather than require further processing or actions by the user to reveal the message.

Onto the colours. Because there are just so many different shades of blue across the map we get a sense of some overall pattern but we can't really tell which are similar to which. How similar is San Bernardion COunty's colour compared to the other dark blues across the other side of the map? It's called simultaneous contrast and is a problem for our map reading. Our perception of a colour (or shades of a colour) varies as we look across the map due to the colours that surround it. Look at the following two grey squares and how they are affected by the surrounding shades:

The grey square differs in perception depending on whether it's surrounded by dark or light.  A darker surround makes us see it lighter than if it has a lighter surround. Now look at how different colours modify the grey square:

The grey squares, despite being the same, take on a perceived tinge of colour based on what's around it. And when the image gets even more complex we have even more difficulty processing what we see. In the following animation, which grey square, A or B, is darker?

Of course, the greys in A and B are the same. In the above diagrams all the grey squares are seen differently simply because of their surroundings. The map of meth labs has over 3,000 counties, each shade of blue being surrounded by it's own different mix of blues.

These perceptual issues are also a problem in classed choropleths of course - but not nearly to the same degree because it's much easier to distinguish and differentiate 5 or 6 shades of blue across a map than it is to try and make sense of several hundred (thousands?) different shades of blue.

And what about labels? Yes we can probably all recognise it's the U.S. I know where my home is so I recognise San Bernardino County. I've no real way of describing where other patterns exist in language that makes sense. Giving people context is important. Interactive maps support this through basemap labels or, again, hover and click...but however you deliver the map, give people a way to reference the patterns they see.

So the take-aways for me...

• It's totals. If you can't or won't change to a rate or ratio then use something other than choropleth like a dot density, proportional symbol, dasymetric or cartogram.
• If you have to use unclassed choropleths then scale your data across the range of colour so that extremeties don't dictate the way values map onto the colours. Make the legend more useful by providing labels at key positions and make your map interactive so people can retrieve values.
• Go with a classed choropleth if you want people to 'see' more than just the extremeties in your data and how different areas are similar to others for all values that display similar characteristics. Learn which classification techniques are going to manage your data most appropriately for the message you want to share.
• Be aware of the problems of simultaneous contrast.
• Include some form of labelling to give people a way of referencing the geographical patterns they see.

Other problems...no real title, no source, no credits, no dates, no contact details. Nothing. Like I said, I don't know where the map came from but as is, it's a fail in every respect.

Finally, I tried to get the data to recreate this as a per capita but after a quick search I wasn't able to find it at county level. Instead I came across this abomination on the Drug Enforcement Administration web site:

I don't even know where to start with this one, and they've made one per year for the last few years. They were clearly on something or other. And if we assume the DEA reporting is accurate (and the most current) AND that the Amazing_Maps one is broadly of the same time period (OK, a lot of assumptions) then what's with San Bernardino having over 300 meth labs given California as a whole has only 79?

Clearly something's wrong somewhere. Amazing map? Possibly. It's just poorly designed and constructed and gives a totally misleading impression of a dataset that cannot be verified. It's another potentially mildly interesting dataset that's poorly mapped.

And by the way, San Bernardino County is the 5th most populous county in the US so per capita...we may even have a paucity of meth labs so a different map might support the assertion we need more to get our supply increased*. Additionally, while the overall area of the county is about 20,000 sq miles, the populated areas are predominantly crammed into the south west corner in an area roughly 450 sq miles...which makes a choropleth map of totals covering mostly desert even less useful (unless the meth labs are in the desert). And all those less important smaller areas...Seattle, St Louis, Tulsa and Grand Rapids. But because of the way the boundaries lie, choropleths are always going to cause difficulties in interpretation. That's the Modifiable Areal Unit Problem...and a whole different blog entry.

* this is a joke