Tag: data visualisation

Book review: The Flawed Genius of William Playfair by David R. Bellhouse

My next review is of The Flawed Genius of William Playfair by David R. Bellhouse. I’ve long had a professional interest in data visualisation, William Playfair is a name frequently mentioned in terms of the invention of several types of chart (line, area, bar and pie charts).

Playfair led an interesting life, fleeing from the French Revolution at one point, and spending several spells in debtors prison.

He was born in Scotland in 1759 and died in 1823. His brothers James and John are notable in the own right as an architect and mathematician respectively.

He apprenticed as an engineer in Scotland and went on to work as a draughtsman for James Watt in Birmingham at the Boulton and Watt works between 1777 and 1780.

It is not discussed in this book but Watt and Boulton were probably close to the origin of engineering drawings as we know them now. They needed them to ensure the parts of the engines they sold, made by multiple manufacturers, would fit together. They also had a business model which saw them paid on the basis of how much money they saved their customers. So Playfair would have a combination of the technical skills required to produce data visualisations, and work for a business that had some call for them. It is interesting to note that another person noted for his innovative visualisations was Charles Joseph Minard, a civil engineer.

Playfair would also likely have had knowledge of Priestley’s Chart of Biography (1765) – a sort of timeline diagram, which plotted the lives and deaths of famous people in history, and the New Chart of History (1769) which showed world history in a similar manner. Priestley was a member of the Lunar Society, as was Matthew Boulton.

At the end of his contract with Watt and Boulton Playfair took on their document copier business, arising from an idea by Erasmus Darwin, patented by James Watt. Playfair seems to have set up the manufacturing process for the machines to a high standard but then left to set up his own business.

This business followed on from the type of manufacturing work that Boulton did, making small metal items with machines. It did not go particularly well, he resumed attempts to set up a manufacturing business on moving to Paris in 1787. His view was that the French were trailing the British in their Industrial Revolution so represented a better opportunity than England, where he would always be competing with Boulton. When in France he also made a proposal to replace the “Machine de Marley” which supplied water to Versailles from the Seine – in this he was unsuccessful. He also set up a bank, as well as being involved in the Scioto Company, which looked to sell land in America to French refugees – an issue here was that the company didn’t actually own any land in America!

Playfair left Paris in 1792, as the Reign of Terror started – he had been peripherally involved in the French Revolution at the beginning but later he became strongly opposed. Supporting the British government in their war with Napoleon – he worked as a journalist, proposed a semaphore telegraph scheme and played some part in a scheme to damage the French economically with a scheme for forging French “assignats” – a form of paper currency used in revolutionary France.

It was just prior to moving to Paris that his writing career started, and his first published works in data visualisation: The Commercial and Political Atlas. The data visualisations were the key novelty here, Atlas uses charts to illustrate economic data. Playfair was showing an increasing interest in economics, meeting Adam Smith in 1787, and also writing a pamphlet on interest rates The regulation of the interest of money. He also edited a version of Smith’s Wealth of Nations after his death.

He also wrote extensively on politics, propounding his views on Jacobins, Catholics, the Irish, and the economy. I was a bit lost here since Bellhouse never tells us what a Jacobin is or the broader historical and economic background. Playfair was in favour of a landed gentry continuing to run the country, and against reform of the parliamentary system. Reviews at the time seem to indicate he was a poor writer with not particularly profound opinions. His British Family Antiquity had the side-effect of bankrupting his publisher, although not Playfair himself (this time).

In his desperation for cash he engaged in low level extortion, effectively writing to people he felt might have money and describing how someone was about to write terrible things about them and he was the man to stop them, for small renumeration. One gets the impression from Bellhouse that this was not uncommon at the time.

Ultimately his attempt to set up a bank in England led to his being imprisoned in debtors prison. His Original Security Bank was established in 1797. It provided notes of convenient denomination in exchange for Bank of England notes. It was clearly designed to take advantage of an evolving situation in banking – the Bank of England had recently stopped exchanging paper money for gold as a result of the war with the French. It presented high “regulatory risk”, in fact the founders, Playfair included were briefly imprisoned for forgery.

As it was the Original Security Bank was quickly wound up, as a result of competition and mismanagement and it is from this bankruptcy that Playfair’s multiple trips to debtors prison arose – the first in 1809. He seems to have come off badly relative to his partners in the bank. Being imprisoned for debt meant that his ability to go into business in future was very limited, hence he leant heavily on his writing. The early 19th century was a different time in terms of how bankruptcy was handled – imprisonment in special debtors prison was routine – a practice that ended in 1869 Debtor’s Act. Playfair formed friendships with other debtors whilst in prison, and these were pretty much the only people he could go into business with – several were outright fraudsters and so this did not go well for him.

In the background to all this he was married to Mary Morris possibly in 1780 when their first child, John, was born although wedding banns were read for them in 1795. They had four children, one of whom was blind and thus needed support throughout her life. One wonders how much Playfair was responsible for the financial support of his family.

I have mixed feelings about this book, it is pretty readable but although the author mentions and illustrates Playfair’s work on data visualisation one gets the impression his interest is more in economics, politics and debt. This may simply be an accurate reflection of Playfair’s life but I was more interested in the data visualisation side of his career.

Book review: Daphne Draws Data by Cole Nussbaumer Knaflic

I recently reviewed Cole Nussbaumer Knaflic’s Storytelling with data, as a result the storytelling team sent me a (pre-publication) copy of their latest book, Daphne Draws Data scheduled for publication 29th October 2024 (UK) and 4th September 2024 (US). This is something of a change for me in the sense that the book is targeted at teaching data visualisation to the 6-9 year old age group. I am 54 – however, I have a 12 year old son and an interest in education. I have never reviewed a book intended for children before.

The first thing to say about this book is that it is beautifully illustrated by John Skewes. As I write this review Daphne (a dragon) is looking out at me from the cover of the book which has put a smile on my face.

The book follows Daphne as she visits various locations, and helps the creatures she finds there by collecting data and drawing graphs (having first reassured them that she was not going to incinerate them!). This is very much like my own career. I particularly liked the visit to the ocean where she draws a graph showing that shrimp and crabs move at the same speed if you allow for the size of the creature. This is quite sophisticated scaling analysis that I’ve taught to undergraduate physics students.

The book finishes with a glossary of chart types which is reminiscent of the material in Knaflic’s books for adults. I was slightly disturbed to see the caption “Eat a rainbow” close to an illustration of some coloured crayons but it is an exhortation for children to record the colour of the food they eat during a day and make a bar chart, rather than eating the crayons!

A children’s book fits very well with the central theme of Knaflic’s work on data visualisation which is the importance of storytelling. To be honest working out who is eating the monkey’s bananas is more engaging than the usual stories we tell in our business presentations.

I guess a key feature of books for children in this age group is that they are read with an adult, I imagine a lot of adults would learn from it too.

Alongside the book there is a website daphnedrawsdata.com which includes resources for educators, amongst much else. This shows how the book fits in with the Common Core requirements in the US school system, I’m sure this will align pretty well with the UK standards.

I’d have definitely bought this book during the COVID lockdowns as material for home-schooling, not only does it cover some data visualisation techniques but it also encourages the data collection that has been central to my life as a scientist. I’d probably also borrow the illustrations for any presentations (to adults) I might give on data visualisation.

Book review: Storytelling with you by Cole Nussbaumer Knaflic

I recently reviewed Cole Nussbaumer Knaflic’s Storytelling with data, as a result the storytelling team sent me a copy of Storytelling with you to review. Storytelling with you is the next step in the journey which started with Storytelling with data, widening the scope to talk more fully about the whole process of presenting from inception to delivery and not being concerned specifically with presenting data.

I’m a data scientist, previously an academic and then industrial research scientist. Presenting has been a constant throughout my career, both as an audience member and as a presenter. Yet it is something in which I have had relatively little training and given the quality of the presentations I have witnessed – I am not alone!

Those with a scientific background will be used to a standard way of presenting results that effectively replicates a scientific paper (introduction, methodology, results, discussion, conclusions). Knaflic’s earlier book proposed a break from this format: using ideas from storytelling to shape presentations. She cites Resonate by Nancy Duarte, as a reference for this approach. Storytelling with you is similar in content to Resonate but feels like a shorter, more focussed book.

The book is divided into three parts: plan, create and deliver. Each part comprises four chapters. Each chapter ends with an instalment of the “TRIX Case study”. TRIX is a trail mix product which requires revision and the presentation is about options for this revision. I really liked this, it enables Knaflic to provide examples of the material in each chapter without having to restate the context for each new outing. I have learnt that macadamia nuts are really important to the TRIX mix!

Planning starts with the audience, not the content. Who are they? What do they want? I find Linkedin is great for getting a quick view of audience members. In terms of content the plan starts with the Big Idea – the sentence that captures what the presentation is about. This is expanded into a full story using a storyboard based on Post-its.

Knaflic is keen on Post-Its for planning and organising material. My tendency when creating a presentation is to open up a PowerPoint file but this forces me into choices on format and so forth that I don’t need to make at the beginning. There is also a challenge in being unwilling to delete slides so carefully and laboriously created!

The section on the theory of storytelling is quite brief. One takeaway for me was to think of the children’s books you know as templates for storytelling. Over the last 10 years or so I have read a lot to my son so I am very familiar with a range of children’s books. I like Dr Seuss, and Julia Donaldson’s books – The Gruffalo, for example – not only do they provide a template for stories, they are designed to be read aloud and provide some ideas for delivery. For fun, you can even think about your presentation in the style of Dr Seuss!

The create section is very practical, including a walkthrough of how to use PowerPoint-like Slide Master – I found this welcome since whilst I am aware of the master slides my use of them is rather primitive. It also talks about font selection, picking a font which has a distinct bold form, and colour selection.

The appendix containing the completed slides for the TRIX case study is quite telling when I compare them to my own: the case study slides contain far less text and effectively no bullet points when compared to mine. The story of the presentation is read from the titles which summarise the slide they sit on rather than indicating the function of the slide.

In terms of content I found the section on images most interesting, corporate templates tend to have a bunch of images included, and I always feel the need to add an image to each slide – which is wrong.

There is a substantial section on delivery. I found the part on introducing yourself quite striking, it talks about picking out the characteristics which you wish to present and relating anecdotes that support them. I found this a bit calculated but realise I probably do this intuitively – I am notorious for my anecdotes!

I was bemused by the vision of Knaflic striking power poses in conference centre restrooms in preparation for presenting! She provides a lot of detail on how she prepares to deliver a presentation. I learnt long ago that practicing the opening is very important, I find it helps me to relax. Knaflic points out that practicing your ending is equally important – it sends your audience off into action.

In common with Resonate and Storytelling with data  the assumption is that you are preparing for a high stakes meeting and you are going to commit a lot of time to this process. Typically I find I make lots of low stakes presentations so there is a degree to which I would adapt the lessons in this book to that scenario. In fact the storytelling team have recognised this, and produced a blog post on a reduced process.

If you’re looking for a readable guide to planning, creating and delivering presentations then this is the book for you!

Book review: Data Points by Nathan Yau

data_pointsI picked up Data Points by Nathan Yau as a recommended book on exploratory data analysis in Storytelling with data. I have previously read Nathan Yau’s book Visualize This.

Visualise This  was very focussed on the technical side of producing data visualisations, with code samples and so forth. This is a “bigger picture” book divided into three sections: context, exploration and presentation.

Context can be summarised as: who, how, what, when, where, why. Context is covered explicitly in the first chapter using the medium of Yau’s wedding photos as an example. Spinning off from here is a mention of the Quantified Self movement, there was a time a few years ago when this was popular – people would record aspects of their life in great detail and build visualisations from them. This was enabled by the growth of the first generations of smartphone which made this sort of data collection easy. Yau points out – and I think all data scientists can agree with this – that most of the job is actually collecting together the data required for a project and getting it into a shape to visualise.

The “Exploration” chapters start with an overview of what a data visualisation is, one of the strengths of this book is the many examples of visualisations, in this case going as far back as William Playfair in 1786 with the invention of the bar chart. This chapter also highlights that a data visualisation can be a flow chart, or it can be an abstract piece of art which is based on data. Yau cites John Tukey’s Exploratory Data Analysis a number of times which was published in the 1970s at a time when the author felt the need to explain that a “bold” effect can be achieved using a pen rather than a pencil. The point being that we now have immense power in readily available software to produce visualisations at the click of a button which would have taken an expert many hours of manual labour in the relatively recent past.

The next chapters provide a summary of how we build a data visualisation starting with the fundamental building blocks: title, visual cues (the data), coordinate system, scale and context elements. The visual cues are further broken down into attributes like position, length, angle, direction, shapes and so forth.

Once this groundwork has been done, there is an extensive taxonomy of chart types including more esoteric plots such as the cartogram (where geographic areas are distorted to show the relative sizes of variables), and radar or polar plots which, along with calendar heatmaps are useful for showing periodic timeseries data.
The “Visualising with clarity” chapter starts to talk about presentation, and how the purpose of visualisations is to allow comparisons. I think the useful takeaway from this chapter for me was that distribution plots are rather more difficult for the lay viewer to interpret than practitioners realise.
I found the penultimate chapter on “Designing for an audience” a little brief. A handy hint here was to design presentations for the audience at the back of the room – nobody likes to hear “this is probably too small for you to see” from a speaker. Another useful tip for making interactive presentations is that people like to find out about themselves, so if you have data on people then make it easy for viewers to “look themselves up” because that’s the first thing they are going to do.

The book finishes with a chapter on technologies, some of them such as R, Adobe Illustrator, Microsoft Excel, Google Sheets, Tableau are still around and remain good choices. Yau’s favoured combination is R with Adobe Illustrator used to polish the results. The Javascript library Data Driven Documents (d3) and Processing are still active. Other systems like IBM’s Many Eyes project, MapBox’s TileMill have disappeared. Javascript Libraries Raphael and the Javascript Infovis Toolkit appear dormant, in the sense that the activity on their GitHub repositories is minimal. Nobody talks about Flash and ActionScript anymore.

Data Points is much more a book about exploratory data visualisation then Storytelling with data, I think Yau believes that exploratory data analysis is an exercise in storytelling. The strength of this book is the wide range of examples used to illustrate the points being made through the book. The style is chatty, it is not a difficult read. It is less focussed on delivering specific lessons in making data visualisations than Storytelling with data.

Book review: Storytelling with data by Cole Nussbaumer Knaflic

storytellingThis book, Storytelling with data by Cole Nussbaumer Knaflic, fits in with my work, and my interests. It relates to data visualisation, an area in which I have read a number of books including The Visual Display of Quantitative Information by Edward R. Tufte, Visualize This by Nathan Yau, Data Visualization: a successful design process by Andy Kirk and Interactive Data Visualization for the web by Scott Murray. These range from the intensely theoretical (Tufte) to the deeply technical (Murray).

Storytelling with data is closest in content to Andy Kirk’s book and his website is cited in the (very good) additional resources list. A second similarity with Andy Kirk’s book is that Storytelling is “the book of the course” –  the book is derived from her the author’s training courses.

The differentiating factor with Knaflic’s book is the focus on storytelling, presenting a case to persuade rather than focussing on on the production of a data visualisation, although that is part of the process. The book is divided into 6 key lessons, each of which gets a chapter, with a couple of chapters of examples, an introduction and an epilogue this makes 10 chapters. The six key lessons are:

1. understand the context
2. choose an appropriate visual display
3. eliminate clutter
4. focus attention where you want it
5. think like a designer
6. tell a story

I think I got the most out of the understand the context and tell a story chapters, technically I am quite experienced but my knowledge is around how to make charts and process the data to make charts rather than telling a story. The understanding the context chapter talks about the “Big Idea” and the “3-minutes story”. The Big Idea is the single idea you are trying to get across in a presentation, and the 3-minute story is the elevator pitch – how you would put your story into 3 minutes. I liked a callout box with a list of verbs (accept, agree, begin, believe…) used to prompt you for what action you want your audience to take having seen your presentation.

The chapter on choosing an appropriate visual display is quite straightforward, Knaflic presents the 12 types of display she finds herself using frequently (which includes simple text, and text tables). This is a fairly small set since variations of bar charts – horizontal, vertical, stacked and waterfall cover off 5 types. This is appropriate, if you are telling a story to persuade then you don’t want to be spending your time explaining how your esoteric display works. Knaflic steers away from specific technology, only mentioning at the beginning of the book that all the charts shown were made in Microsoft Excel and Adobe Illustrator was sometimes used to get a chart looking just right at the end of the process.

There is a list of sins in data visualisation including the reviled pie chart, and 3D plots but perhaps surprisingly the use of secondary axes to plot data on different scales together.

The chapters on eliminate clutter, focus attention where you want it, and think like a designer are all about making sure that the viewer is paying attention where you want them to pay attention. Some of this is about the Tuftian “eliminate clutter” much of which creeps into charts through default behaviour in software. Some is about using gestalt theories of attention to group items together through similarity, proximity and so forth and some is about using pre-attentive attributes such as colour and type face to draw attention to certain elements. This reminded me of The Programmer’s Brain by Felienne Hermans, which links theories of how our brain works with the practices of programming.

The chapter on tell a story introduces some resources on storying telling from playwrights and screenwriters – basically the idea of the three act play with a setup, conflict and resolution. This is a different way of thinking for me, my presentations tend to follow the traditional structure of a scientific paper but it is interesting to see the link with creative writing and drama – which is generally excluded from scientific writing.

One of the lessons I learnt from this book was to make better use of of chart titles and PowerPoint titles, I tend to go for  descriptive chart titles (“Ticket Trend”, to use an example from the book) and PowerPoint titles which simply labelled a section of a talk (“Methodology”). Knaflic encourages us to use this valuable “real estate” in a presentation for a call to action: “Please Approve the Hire of 2 FTEs”.

The six lessons are reinforced with a chapter which covers a single worked example from beginning to end, and another chapter of case studies which looks at fixing particular issues with single charts.

I enjoyed this book, its beautifully produced and fairly easy reading. It also led me to buy two more books Resonate by Nancy Duarte and Data Points by Nathan Yau, and so the “to be read” pile grows again!