Clearly and Simply

Tag: tableau

Choropleth Maps with Tableau

3 different workarounds to create choropleth maps with Tableau

With Tableau Software it is really easy to overlay your data on a dynamic map even without having latitudes and longitudes in the underlying data. However, Tableau does not (yet?) natively support choropleth maps.

We had a couple of posts regarding choropleth maps using Microsoft Excel here on Clearly and Simply. However, creating such solid filled maps to visualize your own data is on the list of wishes of many Tableau users as well (see here for instance).

There is a common workaround for this (described in the Tableau manual as well), using polygon data of the regions to create choropleth maps. Though, this approach needs a lot of additional data in the data source. That’s why I was looking for an alternative. I had a very simple idea, far from being optimal, but still a different approach and much easier to implement and use. Two weeks back, I sent my workbook as a sneak preview to Giedre, a really passionate Tableau aficionado from Vilnius, Lithuania and she was polite enough to make me believe, she would like my approach. In her reply to my email she sent me her brilliant solution of this challenge, much easier and by far better than everything I would ever be able to come up with.

Although she has a blog of her own (add-knowledge), Giedre was kind enough to share her idea with us and she wrote the main part of today’s post. Giedre just started her blog together with some friends recently and there aren’t many posts for the time being. Nevertheless I highly recommend to visit add-knowledge and check from time to time what she will be coming up with. I am looking forward to it!

Today’s article discusses all 3 workarounds of how to create choropleth maps with Tableau: the polygon approach, my simple simulation and Giedre’s brilliant idea using custom shapes. As always, including Tableau packaged workbooks for free download.

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October 28, 2009
Background Image Maps with Tableau

Tableau discovers the world – more detailed maps by using background images and a little trick in Microsoft Excel

Tableau Software offers a very easy way of overlaying data on a map, even without requiring the geographical references (latitude and longitude) in the data source. It automatically identifies field names in your data that are appropriate for visualizations on a map, like state or county and generates the according latitudes and longitudes.

If you are using data of the United States, Tableau provides a very high level of detail (state, county, zip code area) and displays the boundaries and names of the regions on the underlying map. You can even enhance the visualization with a choropleth map showing a variety of predefined US census data.

For other counties of the world, however, Tableau does not (yet?) provide this level of detail. In a data source of Germany, for one, Tableau automatically identifies the 16 states and shows the state boundaries on the map. But that’s it. Higher levels of detail like counties (Regierungsbezirke, Landkreise, etc.) or even zip code areas are not available.

Of course, the folks over at Tableau Software have been smart enough to implement a very easy workaround to overcome this: Tableau provides an option to overlay the data on any given image, e.g. on a picture of a map. Prerequisites for this workaround are a picture of the map and the latitudes and longitudes in the underlying data source. Usually both are easy to find and download somewhere on the Internet. Sometimes, however, the geographical references in your data do not exactly fit to the areas on your map image and Tableau’s visualizations will not be located exactly in the center of the according region.

Today’s post describes this problem using data based on German zip code areas and provides a how-to-tutorial, a Tableau packaged workbook and a little bonus track for my friends in Lithuania.

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September 26, 2009
Week in, week out, Tableau

Week numbers with Tableau

The previous post discussed different methods of calculating week numbers and their effects on analysis and visualizations of data on a weekly basis. The post was focused on using Microsoft Excel.

However, the challenge caused by different week numbering methods is not restricted to Microsoft Excel. I guess every data analysis and visualization software faces this problem.

And so does my favorite: Tableau. There is no built-in way to switch between different week numbering methods in Tableau. But Tableau has the flexibility for an easy-to-use solution. This post provides all information of how to use ISO 8601 week numbers in Tableau, including a Tableau packaged workbook for free download.

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April 13, 2009