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Figure 2-10: Tableau online manual

      Connecting to Cloud Services

      The increasing quantity and variety of data available on the Internet falls into three categories:

      • Public domain datasets

      • Commercial data services

      • Cloud database platforms

      The United State Census Bureau provides free population and business data. The World Bank provides a wide variety of country data, and many other public data repositories have emerged over the past decade. This data can be used to augment your proprietary data.

      There are also a growing number of commercial data sources. Tableau currently provides connectors to

      • Google Analytics

      • Google Big Query

      • Amazon Redshift

      • Salesforce.com

      • Open Data Protocol (ODATA)

      • Microsoft Windows Azure Marketplace

      The Google Analytics connector can be used to create customized click-stream analysis of web traffic. Google Big Query and Amazon Redshift connectors allow you to leverage storage and data processing services offered by Google and Amazon. Both enable you to purchase petabyte-scale database processing capacity on demand. There is also a connector for the popular cloud-based CRM tool, Salesforce.com, as well as the related Salesforce data products (Force.com and Database.com). Microsoft supplies data over the web via the Windows Azure Marketplace DataMarket and was the founding developer of OData (Open Data Protocol), facilitating the creation and consumption of REST APIs.

      Connecting to BigQuery

Let’s look at one of the cloud database platforms, Google BigQuery. The connection screens are displayed in Figure 2-11. You can read all of the details about connecting to BigQuery in the help manual, but the setup requires only two steps. First you log in to your Google account; then you authorize Tableau to access your account.

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Figure 2-11: BigQuery connection

      I’ve used BigQuery to build dashboards that have over 100 million records, with less than two-second latency using a standard Internet connection. More businesses are using cloud data services because they are secure and reliable and perform well in many use cases. Tableau Software also provides a free cloud-based service, called Tableau Public, for publishing workbooks and dashboards.

       Tableau Public

Tableau Public is the largest deployment of Tableau Server in the world. Thousands of people use it to share dashboards and visualizations with others. Figure 2-12 shows an example dashboard published on Tableau Public that was used in a blog post.

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Figure 2-12: Tableau Public

      After you sign up for a free account, two steps are required to share a dashboard on Tableau Public: Build a workbook that includes visualizations and dashboards and then publish the content you wish to share to your Tableau Public account.

      The left side of Figure 2-12 shows a dashboard in Tableau Desktop and the menu options for publishing. To publish a workbook, go to the Server menu, select Tableau Public, and then pick the Save to Tableau Public menu option. If you haven’t logged into the service, you’ll be prompted to log in; then you can define exactly what parts of your workbook you want to publish, along with other options. The right side of Figure 2-12 shows the dashboard in the Tableau Public environment. Note the Share menu option at the bottom right of the image. Clicking that option exposes the embed code and link. If you want to embed the dashboard in a website, you copy that code and paste it into your post. You can also share a link to your published material on Twitter or Facebook.

      Tableau has continued to expand the amount of data that Tableau Public users are able to publish. If you don’t have access to a licensed copy of Tableau Desktop, download the free Tableau Public desktop version. It works just like the paid desktop license with the notable exception being that the only place you can save your work is Tableau Public. Be careful not to publish proprietary data there as it is available to everyone without restriction.

       What Are Generated Values?

      When you connect to a data source, Tableau creates new fields that make difficult tasks easier. You see these fields in the data pane when you connect to a data source.

Figure 2-13 zooms in on the data pane area. If you want to follow along, the companion website contains the workbook used to build the figures in this section. Open that workbook or connect to one of the sample datasets in your saved data sources.

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Figure 2-13: Tableau-generated fields

      Measure Names, Measure Values, and Number of Records are always present. If your dimensions include standard geographic place names, Tableau will also generate center-point geocode coordinates.

       Measure Names and Measure Values

      Measure Names and Measure Values can be used as shortcuts for viewing all the measures in your dataset or to express multiple measures on a single axis.

In Figure 2-14, you can see that two measures are shown, SUM (Profit) and SUM (Sales). These appear as separate columns in the same bar chart. The generated value, Measure Names, is used in the Columns shelf to separate the bars. Measure Names is also used on the Marks card to distinguish color and on the Filters shelf to limit the number of measures shown in the view. Measure Values contains the data, and this is shown as rows as you would expect from this type of bar chart.

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Figure 2-14: Multiple measures on an axis

      The side-by-side bar chart in Figure 2-14 was created by multi-selecting one dimension and two measures. Using Show Me the side-by-side bar chart was selected to create the view. Tableau automatically applied Measure Names to the Columns shelf and plotted both measures on the horizontal axis. The Measure Names quick filter was exposed by right-clicking Measure Names in the Filters shelf and selecting the Show Quick Filter menu option. Using the Measure Names quick filter, you can add or remove measures from the axis. This style of chart works well only if the measures being plotted have similar value ranges.

      There are many ways to combine multiple measures on a single axis. You learn those details in Chapter 3.

       Tableau Geocoding

If your data includes standard geographic fields, such as Country, State, Province, City, or Postal Codes – denoted by a small globe icon – Tableau will automatically generate the longitude and latitude values for the center points of each geographic entity displayed in your visualization. If Tableau doesn’t recognize a geographic dimension, you can edit the field by right-clicking it and selecting the desired geographic unit. Figure 2-15 shows a map created using country, state, and city and then using Show Me to display a symbol map. The map is filtered using the region field to show only the United States.

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Figure 2-15: Automatic geocoding

      You can edit the color of the marks in the map by clicking

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