Back in January, I published a post on how to create a calendar-based view in Tableau. At the time, I mentioned that it had created some buzz within the halls at Tableau-central and that, in part, lead to an invitation from Christian Chabot, CEO, to participate in a new project they were working on.

Well, here is your first peek at that project – Tableau Online!

Essentially, it will allow anyone with Tableau Desktop to publish their workbook online and embed the visualization in their website.

Tableau Online is currently in private beta, but you can sign up for updates here, or click on the logo below the visualization.

Before we get to the visualization itself, here’s what I’ve learned about the project from Christian and Ellie Fields – Director of Product Marketing.

Christian says that the vision for Tableau Online is for it to be “the YouTube of information visualization…” which I interpret as the platform of choice for publishing rich, interactive visualizations online.
Additionally, during a recent discussion with Ellie Fields, I uncovered some of the more nitty-gritty details…

1. It currently only works with local data – basically you need an extract from any source locally on your machine in order to use the visualization with Tableau Online (in all likelihood you will upload a packaged workbook)
2. There have been discussions around an API so that data might be transmitted ‘over-the-wire’, but there are no specific plans for getting that done
3. This is a very early look, the hardware is still undergoing performance testing so be patient if you get an error with the visualization or it takes a while to load; and hey, leave a comment describing what happened!

What follows is a proof of concept based on the calendar view I had developed.

This calendar specifically, and Tableau Online generally is built on the new version 5 platform (there have been some examples creeping out on the Tableau blog). I’ve been working with the version 5 beta so let me tell you about the features from 5 that are important here. Sheetlinks and highlights have been repackaged – and improved – to a new function called ‘Actions’. In this visualization, the calendar filter for year is also applied to the small multiples sparklines below the calendar. This is now very easy to do compared to how sheet links work in version 4. Also, if you click on any particular day within the calendar, that date is highlighted on the small multiples below – enabling this is as easy as hitting a switch (which is basically what you do).

Many improvements and new options have been added to quick filters – but, so far, the biggest improvement IMHO is the addition of the search feature! (Although I wish that the Tableau team had built in direct feedback for when a search fails)

Here are some of the things you can do in this proof of concept.

1. Filter on Year for the whole visualization
2. Select a particular month for the calendar view
3. Highlight any given day in both the calendar and the small multiples by selecting a day in the calendar (you can also select multiple days)
4. Highlight a day in the small multiples only by clicking on a plotted point (or drag select multiple days)
5. Highlight a particular month by selecting the month name in the small multiples column header
6. Lowlight inactive days in the calendar for a particular product category by selecting the category name in the small multiples row header (you can select multiple categories by selecting one category and then either SHIFT or CTRL clicking another category)

The Tableau team and I have discussed many changes to this visualization, but we weren’t able to get them done in time for this post as each change currently requires extensive testing on the new platform, but those changes should be coming soon. Discussed changes include changing the color encoding to profit instead of total sales, and doing a daily sparkline only for the currently selected month and then bar charts aggregated by month for the rest of the months in the currently selected year.

What else would you change/remove/add to this visualization?

Finally, there will be a smattering of sneak peeks going up across the infoviz community so keep your eye on out here and the Tableau blog as those new visualizations go up!

Recently, Tableau published a well-meaning blog post to highlight some of the inherent problems with geography-based visualizations under their tongue-in-cheek “Viz Police” heading. They take issue with a recent visualization published by Media Cloud, a Harvard Law project, showing how various news outlets cover various countries around the globe. The interactive graphic allows you to choose up to three news organizations and then 3 different data sets to compare (top 10 search terms, top 10 term pivot and world map – the visualization Tableau chooses to discuss).

I don’t necessarily disagree with Tableau’s argument, but I think they made several errors in how they chose to communicate it.

Error #1: Bad Blogging Etiquette: The post provides no link to the Media Cloud project and the specific item under discussion. There is no native way for the reader to go back to Media Cloud and investigate the visualization on their own. I wasn’t familiar with Media Cloud so I actually had to Google it to get there.

Error #2: Poor Graphic Use: Tableau chose to use just a thumbnail (the same thumbnail that is provided by Media Cloud) of the infographic. Furthermore, they covered it up with their “Viz Police” badge making it impossible to get a decent view of the graphic. Finally, the way they incorporated their badge into the Media Cloud graphic (it looks like someone screen-shot a layered graphic out of Photoshop or similar) presupposes the bad nature of the graphic. In other words, poor execution of including the badge on the Media Cloud graphic gives the reader the, possibly false, impression that the map is a bad graphic.

Error #3: Lack of a Full-Size Graphic: Tableau did not provide a full-sized version of the Media Cloud graphic. Now, I run hi-res (1928×1208) so I’d argue that the original graphic is too small anyway. But, when you look at the full-sized graphic sans “Viz Police” badge, the errors are not quite as egregious as indicated by Tableau. In the full-sized graphic the Area-bias still exists, but it’s clear that the UK is more saturated than the U.S. on the BBC graphic – when you spend some time looking at it.

Error #4: Misdirection. In attempting to show how Tableau’s solution (circles vs. density) is better, they bring in a completely different data set – “Net Internal Migration by State”. Now Media Cloud does not provide the data behind their graphic so if you wanted to create a comparative graphic in another tool you’d presumably have to jump through some hoops to either get them to provide the data or to estimate the data, but in either case you are not comparing apples and steel ingots ( apples & oranges are, in fact, too similar for the old adage to work) as Tableau is asking you to do in their post.

Error #5: Using area to encode value. In an error similar to the map-density one they are arguing against, Tabeau’s example uses the area of the circles to encode some value – which is not even explained via a legend (the legend only explains the color encoding)! For those that may not know, we humans are not good at estimating area, it’s not what our visual systems are built to do. We tend to over-estimate large areas and underestimate small areas – remember, this is the basic argument against pie charts.

Error #6: Chart Junk. At best, chart junk obfuscates your data making it difficult to understand. At worst, it causes bias or error in judgment of the data. Well, in the Tableau map, the circles have a light-colored border. This border is more evident on some of the plot points than others, creating the misrepresentation that those points are somehow more important. Is the migration to Maine somehow more important than the migration to Minnesota? I don’t really know because they are roughly the same size and color BUT the border on the Maine circle is much clearer than the one on Minnesota – what does that mean?

Error #7: Breaking map conventions. I can’t speak for the rest of the world, but here in the U.S. a circle on a map generally means a population center – a city – and the size of that circle may indicate how big the city is, or all circles are the same size (e.g. no value encoded on the area). So, when I’m looking at a map like this I/we expect the circles to reference a city and these circles do not, they reference a state – Tableau has just broken your mental model of a map! When you use a convention unconventionally and break the standard mental model you typically end up creating cognitive dissonance. I’m not saying that it should never be done, but you have to be very careful. If the confusion throws something into sharp relief that might otherwise be obscured, ok you’ve got a case to do it, but if all it does is create a buzzing between the ears that makes processing the information more difficult you are better off not doing it.

So what? Why am I all in a huff? It’s not because I dislike Tableau – quite the opposite, I am an avid user. I do dislike poorly executed arguments. If the argument is not made cogently, it has holes in it. It looks sloppy and therefore is less effective. Tableau has an excellent point about the pitfalls of area-based information graphics but they’ve shot themselves in the foot with how they argue it and that makes it less likely their readers will understand and trust the argument which well might lead them to not using the learning in their design efforts.

To be honest, I find the whole argument a bit disingenuous. The post argues against a specific type of area encoding – density encoding on geographic areas but Tableau not only allows area encoding on plot types up to and including the ignoble pie chart but their geographic visualizations allow density encoding via the data layers.

BTW, this is a follow-on to the comment I posted on Tableau’s blog. I wasn’t particularly happy with my comment so I rewrote it as a post here rather than editing the comment there.

Source: Media Cloud A Harvard Law | Berkman Center Project

Source: Media Cloud a Harvard Law | Berkman Center project

Source: Tableau

When you’re using Tableau and it is back-ended with a very large data source (an enterprise data warehouse for instance) one of the issues is making the source data that you’re working with manageable. You definitely don’t want to be querying the whole thing every time you refresh a report (probably) as this makes the workbook slower than it needs to be and makes exporting a packaged workbook for others to use nearly pointless (if it will export at all).

One of the simplest things to do is limit the time frame for the report. For instance, maybe the report you’re working on only needs the last 30 days of data or the last 6 months or the last year.

But how do you do this in Tableau?

Beginners, myself included, will just drop the date field of choice onto the filter shelf and manually set the date range required. The problem is that every time you open the report you have to manually adjust your date filter so it’s not helping you as much as it could be.

Enter DATEDIFF. This function – as the name implies – calculates the difference between two dates at a specific granularity. That’s right, it will calculate the difference in dates by number of days, weeks, months, etc. How cool is that?

Ok, so how does that help create a filter that returns only the last N days of data?

It’s so simple you might think the above is a trick question some how.

Before I get started on directions, I’m going to assume that you’re already in your workbook and connected to your data source. For the purpose of this exercise, I’ll be using our friend – SuperStore Data.

1. Start by opening the ‘Create Calculated Field’ dialog box
2. Let’s call this new field ‘30day-Filter’
3. Tab down (or click in) the ‘Formula Field
4. Type in DATEDIFF(
5. The first argument in DATEDIFF is the granularity to calculate with (day, week, month, etc). For our 30day-Filter we’ll use ‘day’
6. So far you should have DATEDIFF('day'
7. Arguments in a function are separated by commas so add a comma after ‘day’
8. The next argument is the start date (e.g. the oldest date) which will be the date from your data source record. In this case, the field we want is ‘Order Date’
9. Our new function should look like this so far: DATEDIFF('day',[Order Date],
10. For the end date, we’re going to use another function – TODAY(). TODAY() takes no arguments and returns the current date from your data source. If you’re connected to a remote data server TODAY() will reflect the date on the server. If you’re working with a local data source (text file, excel, etc) then TODAY() will reflect the time on your local machine
11. So far we have DATEDIFF('day',[Order Date],TODAY()) This is a valid function all by itself and will calculate the difference between the two dates with ‘day’ granularity, but it’s not a filter yet
12. In this case we want a filter that evaluates to ‘TRUE’ or ‘FALSE’ and really, it’s very simple. Just add ‘<=30' to the end of the function
13. DATEDIFF('day',[Order Date],TODAY())<=30
14. Save the calculated metric

notice that in the Dimension shelf your new metric has an icon of T/F. Now we're ready to use the filter! Go ahead and add it to your filter shelf.

A couple of last points on using this filter to make your report dynamic in terms of the date range. Make the filter global - remember the date filter should encompass all of the data you need for the report, and making it global makes it apply to all worksheets automatically. Add the filter to your context - this limits the data Tableau is working with on the server side which should improve the speed of all subsequent queries (less rows to traverse for an answer).

paper visualization

Originally uploaded by charclam

This is an exceptional piece. Beautiful and informative. Make sure to check out Charlene’s post describing the project with more photos.

BTW, see all the contest glory at Information Aesthetics

History of the Internet from PICOL on Vimeo.

This a video history of the Internet using Picol icons – what do you think?