No study of the history of scientific communication can be complete without mention of Joseph Charles Minard, a 19th Century French civil engineer and cartographer.

At the end of his life, Minard created two very famous examples of statistical charts, called flow maps, that every scientist, engineer and student should be familair with.  The first showed Hannibal’s crossing of the Alps (218 BC, Second Punic War), and the second describes Napoleon’s disastrous invasion of Russia (1812-1813).

Both examples are beautiful works of art and masterful examples of evidence.  But they are also more than that, they tell cohesive and interesting stories.  In this post, I thought it might be interesting to take a closer look at the history of Hannibal and Napoleon, and highlight the ways which Minard’s charts help us to explain their eventual outcome.

(Note: High resolution, PDF versions of the two maps are available for download.  These versions have been translated from the original French.  To download, either click on the images, or here for the Hannibal invasion of Northern Italy, and here for the French Invasion of Russia.)

Hannibal Invasion of Italy (218 BC, Second Punic War)

Hannibal was perhaps the single greatest threat to Roman power to ever live.  At the same time that Roman legions marched unopposed through most of the Mediterranean world, Hannibal lead a force of twenty-five thousand soldiers into the heart of Roman territory. He then spent the next fifteen years occupying portions of the Italian peninsula and generally wreaking havoc.  But even though he ravaged the Roman countryside, Hannibal was never successful in subduing Rome.  Ironically, this might be due to one of his greatest exploits: the overland crossing of the Alps.

Hannibal departed his home base in Spain with nearly 90,000 troops (one of the largest armies that had ever been fielded at that point in history) and had a number of early successes.  He marched north over the Pyrenee mountains and into Gaul (modern day France).  He subdued the Celtic tribes and crossed the Rhone River before the Romans could take measures to stop his advanced.  He forged important alliances and found unexpected friends in his fight against the Romans.

After crossing the Rhone, however, Hannibal’s luck began to change.  He received word that a large Roman force was marching from the Mediterranean coast to intercept and destroy him.  As the force outnumbered him by a significant margin, Hannibal was faced with a difficult choice.  Should he stay at his current location and engage the Roman army or retreat and prepare a defense?

Not content with either choice, Hannibal ultimately chose a third option; which, ironically, would have enormous consequences for his overall campaign.  To evade the Romans, Hannibal took the unprecedented action of turning inland and marching over the Alps.  (It is thought that he probably crossed over the valley of the Drome and south of the Col de Montgenevre or near the Col de Mont Cenis.)  This had never been done before – indeed many thought it impossible – and has long been praised as a brilliant tactical decision.

Minard’s reconstruction of Hannibal’s journey shows the journey from Spain, through Transalpine Gaul and eventual arrival in Italy, allows it to be seen a slightly different light, however.  Through use of a flow line, Minard shows how the strength of Hannibal’s army waned through the march, with a disastrous loss of twenty thousand men while passing over the Alps.  This steady loss of strength, subtly reinforced by Minard’s map, helps to explain why Hannibal failed to subdue Rome.

Hannibal’s brilliant tactical decision was also a strategical disaster.  It came at a dramatic loss of men, war elephants, and material with the most disastrous loss being the destruction of his siege engines.  Without the siege engines, Hannibal was never able to successfully attack Rome.  And eventually the Romans realized this and changed their tactics.  Instead of engaging Hannibal directly, they instead fought a long-pitched war of attrition and eventually destroyed the one resource he couldn’t replace: his men.  Thus, even though crossing the Alps helped Hannibal to win a few stunning victories, the decision eventually caused him to lose the war.

Napoleon’s Invasion of Russia (1812-1813)

Like in the case of the Hannibal, Minard’s depiction of the 1812-1813 invasion of Russia also tells an extraordinary story.  It combines information about the size of the army, geography, sub-campaigns and temperature into a single narrative.  This time, though, it is anything but subtle.

Note: Because of  the elegant management of all this information – at any time showing the army’s direction, size, and loss relative to the start – some statisticians and data visualization experts (such as Edward Tufte, Etieene Jules Marey and Howard Wainer) have declared Minard’s depiction of Napoleon’s Invasion of Russia to be the greatest numerical graphic ever created.

From the very beginning, the army met with tremendous hardship.  The cold temperatures and lack of available resources took an enormous toll.  Napoleon had planned on scavenging for supplies to support his massive army, but the Russians had destroyed all of their crops and burned their villages so that Napoleon wouldn’t be able to make use of them.  As a result, the army was heavily reliant on slow supply trains from Europe that were unable to keep pace with its quick advance.  Hundreds of thousands died from starvation and exposure, greatly outnumbering those lost in combat.

Minard’s map shows this trend of devastating loss.  Napoleon’s Grand Army starts out as a wide, brown line to the left of the map.  As the army progresses across Russia, the number of men decreases dramatically.   A few ribbons of men are dispatched to other targets, but by far the majority succumb to the elements.

Eventually, a substantially reduced force (100,000 men, about 20% of those who began the campaign) arrived in Moscow.  What they found did little to improve their circumstances.  The city had been abandoned and burned to the ground.  No food was available.  The only available option was to return to France.

Demoralized and broken, the Grand Army began a slow retreat to the west.  Their progress is shown in the black.  As they crossed the vast Russian wilderness, the temperature turned bitter cold (shown in the bottom third of the map).  When the army arrived at the Niemen river, there were a scant 10,000 troops.  More than 400,000 had died.

Such a devastating loss of life crippled Napoleon’s young empire and left him open to invasion by his enemies.  He was defeated later in 1813 and exiled to the island of Elba.

Conclusion

Minard’s graphics are successful because they demonstrate powerful trends and place evidence within its proper context.  In the case of Hannibal, it shows how he began in a position of strength and then undermined himself through a brilliant tactical innovation.  In the case of Napoleon, it shows how distance and temperature ravaged an army and destroyed an emperor.

The clear evidence and thoughtful presentation define the story, they show where things are headed and help to foreshadow the inevitable conclusion.  For this reason, they are powerful examples of clear communication.

____________________________________________________

Unrelated Thoughts: Re-Visioning Minard with Open Source Tools

Since first seeing these charts as part of an undergraduate statistics course, I’ve been obsessed with them.  I even have a poster sized copy of the Russian invasion (available from Graphics Press) hanging in my office.  Given this obsession, it should come as no surprise that I’ve wanted to include the maps in my book.

There is, however, just one problem; there is not anything new to say about them.  Edward Tufte has held up Minard as a “Da Vinci of Data” for the better part of thirty years.  Nearly every one of his books includes a copy of the maps (in the case of Beautiful Evidence, his most recent work, there is an entire chapter devoted to the graphics; including eight different reproductions).  Other than, “They’re beautiful, study them carefully, read Tufte’s analysis,” there just isn’t that much to say.

That is, until I started looking for examples of scientific illustration that could be reproduced using the vector illustration program, Inkscape. Any such example should have simple lines and clean integration of text and images.  I'm not sure that a better description of Minard's work exists.

The two images above (and attendant PDFs) were my first pass at re-drawing the maps.  And I have to say, I’m rather happy with the result.  For the most part, I was able to get a very faithful reproduction (with the exception of the type face, which I deliberately changed because I hate script fonts), and only required a couple of hours worth of work.

I think that I may have found my book examples.  It allows me to include one of the best statistical charts of all time, talk about flow maps, and even include some interesting how-tos which show how the graphics can be built in an automated fashion.  Which, come to think of it, might just count as a new contribution after all.

Acknowledgements and Further Reading

More information on the book can be found at the publisher’s website.

The source images for the two maps included “Re-Visions of Minard” by Michael Friendly (1999) and the reproductions in “Beautiful Evidence” by Edward Tufte.  Translation for the Hannibal map was adapted from those available on Edward Tufte’s website (Dawn Finley) and sources available at Re-Visions of Minard.  Translation for the Russian campaign map were taken from the reproduction in Edward Tufte’s “Beautiful Evidence”, Wikimedia Commons and sources available from Re-Visions of Minard.

Additionally, the Re-Visions of Minard Website include a number of interesting adaptations of the Napoleon graphic that might be of interest, including both Matlab and GGPlot2 reconstructions.

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Copywrite 2009: Rob Oakes. Apolitically Incorrect

Hannibal, Napoleon, and Joseph Charles Minard

In the past few weeks, I’ve had several observant readers ask about one of my “secret” projects.  They’ve wondered what I’m up to and why it’s detracting from other endeavors.  After answering another query this morning, I decided that it’s probably time to speak openly about it.  So, here’s my public confession: I’m writing a book.

It’s about scientific and professional writing and open source.  Moreover, it will be interesting, intriguing and revolutionary.  (Yes, I have an inflated sense of ego.)

Before really diving into the details, I’d like to give a bit of personal background.  This might help you understand why I’m passionate about the subject.

Background

Ten years ago, had someone told me that I would end up a scientist and engineer, I would have laughed at them.  At the time, I had just started at University and I was fully set on a career in either illustration, design or architecture.  I was much too “visual” and “right-brained” to surround myself by geeks, freaks and nerds.  It didn’t help that I spent a huge amount of time grooming myself to be an “artist”.

During high school, I had been cursed with moderate talent and highly indulgent instructors.  They praised my artwork.  They called it interesting and innovative.  They encouraged me to refine my technique and to major in visual arts.  So, I did.

But as time went on, I realized that I wasn’t very happy.  I realized that I had other interests.  I enjoyed art, I did well in it; but art classes weren’t my favorites.  That honor, as it turned out, was reserved for mathematics and science.

There was also another problem, I found that I lacked the discipline required to systematically create an individual style and build a portfolio.  I wanted create art for myself, not for other people; and that is a fatal flaw in an illustrator (the type of work that most interested me). Illustration, by definition, is work that has been requested for a particular use.  I was more interested in my own whims than those of potential clients.  Thus, not long after recognizing my problem, I decided to go a different direction and changed my major to engineering.

Analytic Design

But even though I condemned myself to a life of investigation and exploration, I remained very interested in art, photography, layout and design.  This interest (and some substantial urging by the doctor I worked for at the time) resulted in a fascination with where science and art seemed to intersect.

And this is when I noticed, like many others, a strange trend.  If you look at the work of those considered the greatest minds in history – Leonardo  Da Vinci, Isaac Newton, Galileo Gallilei, Thomas Jefferson, Marie Curie, Albert Einstein, etc. – you find something intriguing. In nearly every case, those recognized as brilliant weren’t judged solely on the quality of their thinking, but also by how they presented and explained their insights.  Indeed, the thing identified as “brilliance” was not merely exceptional thinking, but clear communication.  After, all, clever thoughts and ingenious solutions mean nothing if they can’t be captured, understood and disseminated.

What is often overlooked, however, is just how much work is required to explain ideas which aren’t inherently simple, and that raises an important problem.  Communication in general, and writing in particular, is very hard.  To distill random and chaotic thought into a coherent and logical narrative requires energy, time and effort.  This is especially true of scientific, technical or professional subjects.

Such documents contain an enormous amount of baggage: figures, theorems, mathematical equations, algorithms, cross references and indexes.  And while such things simplify the life of a reader, they can positively drown a writer.

Tools and Technology

Luckily, however, there are tools and technologies that can simplify the organizational side of communication and allow for a writer to focus on the important parts: words, pictures and evidence.  But finding these tools and making them work together can be a very daunting task.  And that’s why I’m writing a book.

In its pages, I want to introduce principles and ideas that are characteristic of good communication.  For example, why was Albert Einstein able to convince both scientists and the general public that E=MC^2?  Why do we still read the scientific treatises of Isaac Newton or Charles Darwin – centuries after their ideas have been edited, amended, extended and restated?  Why does scientific communication often fail and what can be done to prevent breakdowns or misunderstanding?

Then, I want to show how those principles can be applied.  I’ll look at open source tools and how they work.  What programs are available for capturing information and references, organizing thoughts, and eventually creating a cohesive manuscript?  How can open source tools be used to create beautiful charts, maps, graphs and tables?  How can the process of collaboration be simplified?

Finally, I want to show why open source is awesome.  I want to demonstrate why it is functionally superior to proprietary alternatives; and I want to do this in a way that shows it to be accessible.  (Far too often, I find that people are afraid of open source because they view at as “complicated”, which is very unfortunate.)

Conclusion

When I first switched from art to science, I found myself confused, lost and overwhelmed.  Not only did I need to adjust to a completely new discipline and culture, but I also found that no one used the same computer programs!  And while it took some time to understand why, once I did, I realized that I would never go back to the “old” way of doing things.

Thus, I’m writing the book I wish someone had given me as a new science student; a book that explained the functional bits of scientific and professional writing with lots of examples, code, and pretty pictures.  This is what I’ve tried to put together, something that is part theoretical treatise but mostly instructional manual.

So, for those of you who have wondered where I’ve been and where I’ve wandered; that’s the answer.  I’m writing book.  The good news, however, is that it’s nearly finished.  And it’s in a state where I can start to share thoughts and examples from its chapters.  In the next few months, expect to see some of that information here.

But because I’m passionate about the subject, I would love to hear others have to say.  What makes for a good piece of informative writing?  What are examples of clear communication?  What lessons might we in the sciences learn from others?  And what tricks do you have for being more efficient?

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Copywrite 2009: Rob Oakes. Apolitically Incorrect

About This Book Thing