In the previous post, the data was widely spaced, so it filled a base 10 log scale with two decades with only a reasonable amount of space above and below the data.

If the data isn’t spread out so nicely, you lose the opportunity to use a regular logarithmic axis. We’ll look at this for Excel 2003 and for Excel 2007, and then we’ll look at native logarithmic axis labeling.

Excel 2003

The data in the table below has a narrow range, from 8 to 12, and the range spans a power of ten.

Here is the data charted using a linear axis.

When we apply a logarithmic scale axis, the data spans across 10, so by default the axis ranges from 1 to 100. The data is squeezed into the middle of the chart.

Since Excel 2003 only permits the axis to begin and end at powers of ten, we’re stuck with this, and the fanciest labeling doesn’t make the data easier to read.

Following the steps in Custom Axis, Y = 1, 2, 4, 8, 16 we can plot the logs of the data on a linear scale, from log(8) = 0.903 to log(12) = 1.079.

We can hide the default labels, add a series with points where we want our custom labels using log(Y) data, and use the Y values as data labels.

Here’s the chart. With such a narrow spread in the data, it’s not immediately apparent that the Y scale isn’t linear, but if you took out your ruler (you still have one of those, right? you’re not completely digital?) you can tell that the span between 8 and 9 is larger than that between 11 and 12.

Excel 2007

As described in Custom Axis, Y = 1, 2, 4, 8, 16, Excel 2007 makes working with log scales a bit easier.

Here is the data plotted on a linear scale.

Here is the same chart, with the scale transformed to a logarithmic scale, using the default base 10. Same as Excel 2003.

Here the log scale has been changed to base 2.

In 2007 we can change the min and max of the log axis to values other than 10 (i.e., other than the base). Here the axis ranges from 8 to 80, still a decade on the base 10 log scale. Instead of the minor ticks being located at multiples of ten (20, 30, 40, 50,…), they are located at multiples of 8 (16, 24, 32, 40,…)

We can also change the maximum so that the axis spans a non-integral number of cycles. Here the maximum is 12 to fit the data. This looks the same using base 10 or base 2.

We don’t get labels other than at the minimum because the axis spans less than a power of base 10 or of base 2, but we can use the same protocol as above to add points with data labels. The advantage Excel 2007 has over 2003 is that we can use the actual values to locate the points, and we can simply use the Y value data label option. In Excel 2003 we had to use the log of the Y positions, and either manually edit the labels, or use a third-party add-in. (Even though the add-in is great, it still is something extra required.)

Finished. Again, just like Excel 2003, only easier.

Log Axis Labeling

Below are a few variations on a log axis that spans six cycles. These were produced in Excel 2003, but they would be the same in 2007. The scales show both major and minor tick marks, which are available for any base except for 2.

The first scale runs from 1 to 1,000,000, and the second from 1/1,000,000 to 1. The third and fourth run from 1 to 1,000,000 like the first, but instead of the default major unit (major tick spacing) of 10, the third has a major unit of 100 and the fourth of 1000. The minor tick spacing is ignored.

If you use the default major unit, minor ticks are placed at multiples of the number at the start of the cycle. In the Excel 2007 chart above that used a base 10 log scale and ranged from 8 to 80, the minor ticks were at multiples of 8 (16, 24, 32, 40,…). In our first axis below, the bottom of the decade is at 1, so minor ticks are at multiples of 1 (2, 3, 4, 5,…). The the second axis, the bottom of the decade is at 0.1, so minor ticks are at 0.2, 0.3, 0.4, and so forth.

In 2003, when the non-default major unit is used, the space between major tick marks is divided up as if it were a single cycle (not two or three. Instead of the ticks being located at 2, 3, 4, etc, for a major unit of two cycles, the minor ticks are located at the square of the one-cycle values, that is, at 4, 9, 16, etc. For a major unit of three cycles, the minor ticks are located at the cube of the one-cycle values, that is, at 8, 27, 64, etc. Interesting.

Excel 2007 does this a bit differently, and for a two-cycle major unit, it makes sense. The first pair of axes below show a scale of 1 to 100, first with the major unit defined by the default one cycle, then by two cycles. I’ve added labels to many of the minor ticks to help illustrate this behavior. The two cycle axis has the first minor tick where the first cycle ends and the next cycle starts, then the rest of the ticks are where they were defined for the second cycle. This puts the ticks at the very logical values of 10, 20, 30, etc.

With larger spans between major ticks, Excel 2007 seems to get confused. The second pair of axes shows three cycles with major units of one and three cycles. The three-cycle axis places minor ticks where the two-axis tick did in the first instance, at multiples of 10 between 10 and 90. There is no tick at 100, nor any between 100 and 1000. Not shown is a four-cycle axis. This puts minor ticks at multiples of 10 between 10 and 90, and at multiples of 1000 between 1000 and 9000, but skips the decade between 100 and 1000.

– - –

This is pretty obscure. It doesn’t make sense to use multiple cycles as the major unit. In a two-cycle major unit, Excel 2007 uses more logical minor tick spacing, while the minor tick spacing is broken for larger major units.  Excel 2003 uses a consistent minor tick spacing which is logical in its own way, but not readily understandable.

Sometimes you’re working on the keyboard, and don’t want to reach over to the mouse to right-click, especially if the object you want to right-click on is already selected. Perhaps the object is too small to click on reliably. Or maybe it can be most easily selected using the arrow keys, like a chart series that is off-scale or hidden behind another series.

If the object is selected, you don’t need to use the mouse to activate the context menu. Near the right end of the bottom row of most keyboards is a button decorated with an icon, which if you look closely, shows a menu and an arrow cursor. I’ve highlighted this button with a green rectangle in this photo. Pressing this button is the same as right-clicking on the selected object.

This button is a nice little timesaver. It’s almost as useful as the Delete key.

Here are a couple short items of interest, so I don’t feel too guilty about not writing.

Office 2010 Technical Preview/Beta

The big news of the week, in case you just crawled out of your cave, is that Microsoft has finally released the Office 2010 Beta. There is a lot of happy noise surrounding this release, both from Microsoft and from a bazillion other places. Some of these other places are just rehashing the MS press release, but some actually seem to have looked at and tried out the beta.

I haven’t had time yet to install the beta. The old computer that I had to replace last week is now inexplicably working. Nobody who has touched the machine remembers doing anything that would have made any improvement, so maybe the computer needed a break. Well, break’s over, and ready or not it’s getting the 2010 Beta this weekend.

I’ll be testing the Beta, which has the same installed version of Office as the Technical Preview, but the Beta program includes a means to report bugs and make suggestions, nyah-nyah. An interesting break from the past is that Microsoft has decided since the Technical Preview has the same client apps that the Beta testers receive, it counts as being released to the public, and is not subject to NDA. So I might be able to write some interesting articles about it.

Stay tuned.

50 Google Charts Tricks.

If you’re tired of hearing about Excel, or if you just need something to read while you wait for me to start writing again, you can check out this post, which contains a categorized list of links related to Google Charts. I’ve only looked at a couple so far, but if this web thing truly is the wave of the future, then web apps is where it’s at, and we’ll see a real competition between Google and Microsoft over spreadsheets, in fact, all manner of documents, and data presentation.

When the PC started its shutdown trick last month, I did a full backup, and Mozy (my online backup service) seems to have done its stuff through the end of last week, so I probably didn’t lose more than a few days work.

The service guy at Staples (where I bought the sick laptop and most other of my computers) is extracting the contents of the hard disk to a new 1.5 TB external drive. I was planning to put all these files onto my old desktop until I could justify a new laptop, but Staples had an attractive deal on a new laptop, and my will was weak. Wide screen, Dual-core AMD processor, 4GB RAM (well, 2.75 with a 32-bit OS), 320 GB hard drive, so I can store more than about three VMs.

After the files have been recovered, we’ll see if something easy like a new fan will revive the box. If so, I’ll have a spare. If not, I’ll take it and a couple other old machines to be recycled.

My first move, once I got the new laptop home, was to wipe out the Vista installation with all the OEM crap (Norton, Office 2007 Trial Version, etc.), and install the Windows 7 RC. It looks a lot like Vista, and it runs smoothly. Lots of RAM helps here. Then I installed Office 2003 and VirtualPC. I’ll set up a few VMs with XP, Vista, and Windows 7, and Office 2000, 2003, and 2007.

It used to be fun and exciting to get a new computer. Now it’s more of a pain. Install this, uninstall that, try to remember your favorite settings and shortcuts and zillions of passwords. I’ll be back in action in another day or two.

I had a web meeting with a couple of my clients this week. Normally I use GoToMeeting for this purpose, but the client set it up, and we used WebEx. When I selected a service a few years back, I rejected WebEx in favor of GoToMeeting, because I thought GoToMeeting had the nicest, smoothest, most intuitive interface of all similar products. The WebEx experience this week reminded me why I chose GoToMeeting, and showed that WebEx has not progressed in several years.

I had to download the WebEx software. The download was fine, but installation was a little shaky, and when installation was finished WebEx started, but unlike GoToMeeting, it didn’t remember which meeting link I’d clicked on to initiate the download and installation. Fine, I reopened the email and clicked again on the link. At one point I had to take control of another participant’s desktop, which is intuitive in GoToMeeting: click on a clearly-labeled button. In WebEx I had to right click on an unlabeled icon (without even a tooltip) to request control before the other user could grant permission, and he had to grope around to find the control to accomplish that. The WebEx connection was not as smooth or as quick as GoToMeeting, and the image quality was so poor I could barely read any text. There also didn’t seem to be a VoIP option. The final insult was that when the meeting ended, FireFox crashed.

I asked my client why they use WebEx; the answer was that the boss uses a Mac so they couldn’t use GoToMeeting. Well, a quick trip to their web site showed that this was untrue. So I emailed the client to say that (a) GoToMeeting works for Macs, and (b) the boss should get a real man’s computer.

I have a standard subscription to GoToMeeting, which runs $49/month, and allows unlimited meetings with up to 15 participants. I’ve used it to diagnose problems on client machines, because seeing what’s happening is much more informative than “I get an error”. I use it to demonstrate add-ins and techniques, because I can show something on my desktop, then watch and direct on the users’ desktops, and they learn better than following even a detailed web page. I used it to help my daughter, who’s away at college, clean some malware off of her computer. The subscription paid for itself when one user, who fancied himself as something of a programmer, asked me to walk him through the code so he could document it (he added comments like “Declare Variables”, “Start Subroutine”, and “Set bTest Equal to True”): though remarkably tedious, it was uch better on screen than over the phone..

I’m not getting any benefit from saying this, but I’ll say it anyway: GoToMeeting is by far the best web meeting service I’ve ever used.

I guess Chandoo and I touched off a major tempest in a teapot with our joint announcement last week of our New Feature: The Chart Doctor. Without realizing it, we had used the name of a similar feature on another blog.

As Kelly O’Day of ProcessTrends.com wrote in The Original Chart Doctor:

I started my Chart Doctor feature at ProcessTrends.com way back on 9/30/06….

On 6/12/09, 21 months [JP: he meant 33 months] after I introduced Excel Chart Doctor, Chandoo and Jon Peltier announce that they are adding a Chart Doctor feature to their blogs.

… All I ask … is a little respect and credit if someone uses my ideas or work.

The last line, implying that Chandoo and I had somehow taken Kelly’s ideas or work, was a little insulting at first. But perhaps Kelly felt insulted that Chandoo and I had stolen the name of his feature, so I decided to cut him some slack and figure out what was going on.

To identify something that is done poorly, and to suggest ways to improve it, is a common format. It’s common in how-to articles and tutorials, it’s common in blog posts, it’s common in classrooms. Kelly has used this format on the Chart Doctor page of his web site; Kaiser Fong of JunkCharts.com has used it; Chandoo has also used it. I have used this format on my web site and on my blog. Kelly has used this format on his blog, using some of my Excel tutorials as the “before” and his work using R as the “after”. Nobody here copied this format from anybody else; it’s been deeply ingrained in us.

Ironically, the first before-and-after post on my nascent blog, Clustered Bars as an Alternative to Stacked Bars or Bubbles, was posted on March 7, 2008, the same day as Showing Categorical Data on Trend Chart, the most recent example on Kelly’s Chart Doctor page. I must have forgotten about Kelly’s Chart Doctor page in the intervening 15 months. If I had remembered, I would have suggested a different name to Chandoo.

If Kelly had emailed us, Chandoo and I would have graciously accommodated his request. I imagine we will pick another name for our feature, and continue ahead with our renamed new feature. Anyone have any clever ideas? Anyone have this kind of feature that we should avoid?

Deja Vu All Over Again

At the end of his post, Kelly asks,

Should I chalk this up to another Excel Deja Vu All Over Again?

I had to go back to this post to guess what Kelly was talking about. It turns out that in May 2006, Kelly had posted a chart showing crude oil prices in adjusted 2004 dollars, which used error bar callouts for its event labels. The deja vu part of this was my two-part series, Replacement for an Oil Price Radial Chart and Callout Labels with Error Bars. I had done a “Chart Doctor” style post, in which I started with an unfortunate radial bar chart of crude oil prices (not inflation adjusted) and turned it into a time series (line chart), using error bar callouts to label events on the chart.

Kelly thought my chart looked familiar, and there may have been a hint that his chart had inspired my own. But it didn’t happen that way. I had downloaded data from DOE and linked to it in my post, so that I could show the same data as in the awful chart I was reconstructing. It’s a coincidence that Kelly and I were both plotting the price of crude, but not at all unlikely; Excel is used to plot all manner of economic data, and crude oil is a rather important commodity.

The error bar technique I used for creating label callouts also did not originate with Kelly’s earlier post. This is a well-known method for labeling charts. John Walkenbach wrote about it on page 274 of his first Excel Charts book, published in 2003 by Wiley, and I’d known about this labeling approach long before I edited John’s book.

So Kelly’s strange case of deja vu was just that: he was seeing something that was similar to something he had seen before.

Excel and R

Let’s put all of the controversy aside, and talk about R, the open source statistics and graphics package. R is a scripted language with a collection of libraries to automate certain tasks.

R is gaining traction in some specific areas of industry and especially academia. Kelly O’Day has done a lot of work to bring R into the hands of ordinary users. He has posted a lot of tutorials complete with R scripts, demonstrating how to use R. Very often, he’ll take one of my Excel tutorials and show the same approach in R. Because of Kelly’s many tutorials, I’ve come to recognize that R has some outstanding computational and graphical capabilities. One of these days, I’m going to learn to use R.

Despite its benefits, I think it will be some time until R becomes part of the average spreadsheet user’s graphics arsenal. In Excel, you often have to stand on your head, kicking and screaming to make Excel do what you want. But for all of its frustrations, it’s Excel. Everyone has it, and most users think they’re experts. People are used to the effort required to do what should be easy, and they are even somewhat proud of the workarounds they have developed.

R may be easier to use to accomplish various statistical and graphical tasks. But R is a separate application, requiring an interface to Excel, and requiring users to learn a new program. It is often difficult enough to get IT departments to install a simple Excel add-in, never mind a new application. The learning curve may not be too steep, but it still represents a barrier to implementation.

Mike Alexander has decided to start his own blog. It’s called Bacon Bits, which fits into the whole Data Pig Technologies theme.Mike promises to add significant new posts every day, and as he says “Don’t worry, it will be great…you’ll love it.”

Mike’s a fellow Microsoft Excel MVP, and the two of us run a three day Excel Dashboard and Visualization Bootcamp a couple times per year, most recently last month in Dallas. We’ll probably do it again in September or October.

Advanced Excel Conference

Bob Umlas and I are hosting an Advanced Excel Conference next week, Wednesday and Thursday, June 17-18.

It’s two days of Excel programming and charting, and despite the late date, it’s not too late to sign up.

Bob’s yet another Microsoft Excel MVP, and he’ll be teaching Intermediate Excel VBA and Excel UserForms. I’ll be covering Advanced Charting and Using Excel with Other Applications (mostly PowerPoint).

Busy June

As anyone with kids knows, June is the busiest month of the year. This year has been particularly busy, with the high school graduation of my middle daughter (technically her graduation was late in May, but it all blurs together).

There’s also the proms, year end concerts and recitals, the sports banquets, the awards nights, finals, and lots of other fun activities spread over May and June.

June’s full of other occasions as well. Today is my anniversary (26 years), and tomorrow’s my birthday (the big five-oh!). Another daughter has a birthday next week. And I want to wish a belated birthday to Kim and Kelley Deal (only one day late).

Guide to Microsoft Excel 2007 for Scientists and Engineers

By Bernard Liengme, Retired Professor of Chemistry and Lecturer in Information Systems St Francis Xavier University, Nova Scotia, Canada, and Microsoft Excel MVP.

This is a follow-up written explicitly for Excel 2007, but much of the book is really version-agnostic. It assumes little foreknowledge of Excel, and starts out with the preliminaries, such as entering  simple formulas and printing a worksheet.

The book proceeds to advanced topics, including VBA programming, advanced data analysis and display, and finally into modeling of physical systems.

Professional Excel Development – 2nd Edition

By Rob Bovey, Dennis Wallentin, Stephen Bullen. and John Green.

The first edition of this book was considered the seminal book on Excel development. It covered many advanced topics, in such a way that a user understood the topics and could implement them (unlike certain renowned help files).

This edition is as advanced as the first edition, and several sections have been added or enhanced. I already have sticky notes in a few chapters I need to read in more detail. There is a section on working with the Excel 2007 ribbon, and the coverage of VSTO and .Net has been changed from practically just a sidebar to several chapters, thanks to the fine efforts of Wallentin, a new author in this volume, but no stranger in the Excel blogosphere.

Now You See It: Simple Visualization Techniques for Quantitative Analysis

By Stephen Few, leading authority on practical information visualization.

Stephen Few stands out among infoviz experts in that his writings are approachable by “mere” typical users, his style is easy to follow, and his examples can be implemented by almost anyone, with almost any software package. Few backs up his assertions about visualization techniques with insights from the field of human cognitive science, not simply graphic design rules handed down from the mount. Few isn’t the biggest fan of Excel, but he acknowledges that it is the most prevalent data visualization package, and his approach can be followed in Excel.

Few starts with a brief history of visualization: “[Scottish social scientist William] Playfair invented the bar graph, was the first to use line graphs to represent change through time, and, on one of his off days, invented the pie chart.” This fluid style permeates the book, and makes it an enjoyable and informative read.

Stay Tuned

As time allows, I’ll finish these books and add more detailed reviews. I’ll also provide links to reviews by others.

I have no punch line, because this left me speechless. Going way too far in support of a bad metaphor. Wouldn’t some kind of probability plot or histogram have been easier to read? Like this quick sketch by krees.

Speaking of MIT, sort of

From FlowingData I read about a new open-source visualization framework called Axiis, which has been released under an MIT license. I present the visual used to herald this release.

Well, they got some of the the medal counts wrong, but there are other problems.

I’ve reduced their stacked donut wedge structure to a simpler pie chart.

Look okay, until you realize that there were more than eleven countries earning medals. Here is the entire list.

Hmm, about a third ov the medals were unaccounted for, and there’s no indication of that in the chart. In this bar chart I’ve lumped thee missing 1/3 of the medals into an “Other” category.

Another problem with the Axiis chart is shared by all pie-type charts. The points have no common reference point: the starting points of each angular measure starts where the previous measure ends. Can you tell from the Axiis chart whether the US won more gold, silver, or bronze medals? Did China or Russia win more silvers?

Plot the data in a boring old bar chart, and ask the same questions.

Much easier to make comparisons.

The software itself looks interesting, but judging from this and other samples, there seems to be no guidance to help the user avoid ineffective chart designs.

Bill Gates Does TED

Bill Gates poses a couple of problems for us to solve. How do we eradicate malaria, which is one of the three largest contributors to childhood deaths, and how to we transfer good teaching practices from the top 10% of teachers to the rest, in order to bring the US back to parity with thee best in the world.

Thanks Alvaro for the link.

In Spinning multi-color, Kaiser of JunkCharts brings to our attention a worthwhile study of greenhouse gases, and a decidedly not worthwhile visualization of the same. It’s very colorful, but not easy to interpret. In fact, the colors are distracting, and it takes some poring over the graphic to realize that the smaller pie charts represent unequal portions of the larger one.

Image created by Robert A. Rohde / Global Warming Art.

Kaiser provides a nice analysis of this ineffective visualization, and creates an alternative bar chart. Please visit his post to see what he has to say.

2009 XLCubed Dashboard Competition

XLCubed and BonaVista Systems, makers of MicroCharts sparkline software for Excel and the new Chart Tamer add-in for Excel, announce the 2009 Excel Dashboard Competition.

Like last year, they are soliciting entries from real business applications, produced using only Excel and their own Excel add-in products. This is a good opportunity to sharpen your dashboard skills, and if you don’t have the BonaVista add-ins, it’s a good time to download the 30-day trial versions.

Every Picture Tells a Story, Don’t It?

Chandoo reminds us that A Good Chart is a Story with this graphic showing that incidence of obesity increases as the time spent eating decreases.

Obesity and the Fastness of Food

Part of the fun is in the interpretation. Is this actual time spent eating, or reported time spent eating? Does it include time spent on the couch drinking beer and eating chips? Or maybe fast food really is bad for you.

Misinterpretation is fun, too. Eat more and weigh less. In my dreams.

Chando makes a good point: A good chart tells a story, and if you have no story, maybe you should spare us and keep the chart to yourself. Although that didn’t stop Dilbert in the cartoon I posted on Pi Day:

Dilbert comic strip for 03/07/2009 from the official Dilbert comic strips archive.

Testing for Bugs at xkcd

xkcd comic strip for 05/13/2009.

I’ll never read the disposition of a bug report the same way again.

Excel Dashboard and Visualization Bootcamp

Next week is the Bootcamp in Texas. I’ll probably be posting lightly.