As the demand of visualisation is increasing day by day , we have different tools to implement visualisation.Tableau is one of the most efficient tools available for data visualization.
Tableau stores and extracts data from cloud databases, spreadsheets, in-memory data engines etc. and transforms this data into graph-type visualizations.Inorder to learn Tableau you need to install Tableau.
Let us learn how to Download Tableau Public
Tableau Public is a free platform to explore, create and publicly share data visualizations online.
So, it is up to you and what you plan on using this tool for. You can either download Tableau Public for free or pay for Tableau’s desktop version. Both options would allow you to follow along. There are some limitations to the public version, however, especially if you want to integrate Tableau and other programming languages like SQL, R, and Python. To do that, you’ll need Tableau Desktop. But if you’re just starting out, Tableau Public will do just fine as it allows you to practice at will.
As you can see, the first result points to Tableau’s website at www.tableau.com. Simply click on the link and it will direct you to the Tableau Public domain.
Provide an E-mail Address
Great, you’ve reached the main page. There, you’ll see a bar that will prompt you to download the app. All you have to do now is provide an e-mail address:
Once you’ve done that, an ‘.exe’ file will download Tableau Public automatically on your computer.
Install the Software
Let’s open the ‘.exe’ file. Before you begin the process, you have to agree to Tableau’s terms and conditions, and then click the Install button in the corner
Visit this website for more details
You get this window to download tableau, click on install
Learn foundational tableau concepts and terminology
When we open a worksheet in Tableau we can see this workspace where we make visualization for the data.
Picture of workspace.
-consists of menus, a toolbar, the Data pane, cards and shelves and view area
Dimensions and Measures
Dimensions contain qualitative /descriptive values (such as names, dates, or geographical data). You can use dimensions to categorize, segment, and reveal the details in your data. Dimensions affect the level of detail in the view. Measures contain numeric, quantitative values that you can measure. Measures can be aggregated. Dimension is the qualitative information of the data, and Measure is the quantity of the data. Location, country, date is the dimension of the data. Data that contains numbers like profit, discount is a measure of the data.Dimensions can be organised to hierarchy.You can hide fields that are not used.You can group fields to folders ,inorder to organise them.
The Tableau workspace consists of menus, a toolbar, the Data pane, cards and shelves, and one or more sheets. Sheets can be worksheets, dashboards or stories. Every worksheet in Tableau contains shelves and cards, such as Columns, Rows, Marks, Filters, Pages, Legends, and more.
Workspace area is consisting of data pane ,column ,row and the place where we see visualisation/charts
Leftmost of the workspace is the data pane.Data pane displays all the fields from data source.The fields are grouped by data source table.Within each table there is a horizontal line.The fields that are above the line are called Dimensions.Below each table's horizontal line there are fields that are called measures
The largest space in the workspace is view, the view is where your data visualisation displays.You can build one visualization per sheet.
At the bottom of the sheet ,use sheet tabs to add additional sheets.You can combine sheets to create Dashboards and stories.At the top of the workspace use toolbars to access commands,analysis and navigation tools.
Drag fields from the data pane to the shelves and cards to build each visualization.
Show Me: Helps you choose a view type by highlighting view types that work best with the field types in your data. An orange outline shows around the recommended chart type that is the best match for your data. For more information
Columns and Rows shelves
Drag fields from the Data pane to create the structure for your visualizations.
The Columns shelf creates the columns of a table, while the Rows shelf creates the rows of a table. You can place any number of fields on these shelves.
When you place a dimension on the Rows or Columns shelves, headers for the members of that dimension are created. When you place a measure on the Rows or Columns shelf, quantitative axes for that measure are created. As you add more fields to the view, additional headers and axes are included in the table and you get an increasingly detailed picture of your data.
Figure: Bar chart representing hospital data set ( Left side you can see tables-Ambulatory visit, Discharges.You can see horizontal lines dividing dimensions above the line and measures below the line for each table)
Drag and drop length of stay from Discharges table to the Columns ,Right click length of stay -take measure -click on the Count-to take count of length of stay(how to use CNT() function) and Discharge disposistion from Discharges table to the rows.
You can see column and rows in the picture .Columns- we can see the count of length of stay using CNT() function. Rows we can see Discharge disposition(Expired,Home,Transfer).This is how we make a bar chart,
Among column and row,One should be a measure(count, sum etc) ,other one Dimension.This is a horizontal bar chart ,we can make it vertical bars by interchanging columns and Rows.That is Discharge Disposition comes in Columns and CNT(Length of Stay) in rows.
How to take Count function from the Length of stay is shown.Measure comes in green color.Dimensions in blue color.
Tableau displays data using marks, where every mark corresponds to a row (or a group of rows) in your data source. The inner fields on the Rows and Columns shelves determine the default mark type. For example, if the inner fields are a measure and a dimension, the default mark type is a bar. You can manually select a different mark type using the Marks card drop-down menu. The Marks card is a key element for visual analysis in Tableau. As you drag fields to different properties in the Marks card, you add context and detail to the marks in the view.
By default Marks card takes automatic as Bar chart.You can select from the droplist which type of visualisation you want for your use case.
You use the Marks card to set the mark type (see Change the Type of Mark in the View), and to encode your data with color, size, shape, text, and detail.
After you add a field to the Marks card, you can click the icon next to the field to change the property it is using. You can also click the property buttons in the Marks card to change those settings.
Many properties can have multiple fields. For example, you can add multiple fields to Label, Detail, Tooltip, and Color. Size and Shape can only have one field at a time.
Here CNT(LengthOfStay) comes in color and size.Primary Diagnostics is dragged into the Label(Text).
Drag dimensions, measures, and date fields to the Filters shelf .Another way to create a filter is to drag a field directly from the Data pane to the Filters shelf.
When you add a field to the Filters shelf, the Filter dialog box opens so you can define the filter. The Filter dialog box differs depending on whether you are filtering categorical data (dimensions), quantitative data (measures), or date fields.
Filter categorical data ( Dimensions ) Dimensions contain discrete categorical data, so filtering this type of field generally involves selecting the values to include or exclude.
When you drag a dimension from the Data pane to the Filters shelf in Tableau Desktop, the following Filter dialog box appears:
You can select fields from the list by checklisting the fields needed for your visualisation.If null values are there you can deselect it.
General: Use the General tab to select the values you want to include or exclude.
Wildcard (Tableau Desktop only): Use the Wildcard tab to define a pattern to filter on. For example, when filtering on email addresses you might want to only include emails from a specific domain. You can define a wildcard filter that ends with "@gmail.com" to only include Google email addresses.
Condition: Use the Condition tab in the Filter dialog box to define rules to filter by. For example, in a view showing the average Unit Price for a collection of products, you may want to only show the Products that have an average unit price that is greater than or equal to $20. You can use the built-in controls to write a condition or you can write a custom formula.
Top: Use the Top tab in the Filter dialog box to define a formula that computes the data that will be included in the view. For example, in a view that shows the average Time to Ship for a collection of products, you can decide to only show the top 15 (or bottom) products by Sales. Rather than having to define a specific range for Sales (e.g., greater than $100,000), you can define a limit (top 15) that is relative to the other members in the field (products).
Filter Quantitative data (Measures)
Measures contain quantitative data, so filtering this type of field generally involves selecting a range of values that you want to include.
When you drag a measure from the Data pane to the Filters shelf in Tableau Desktop, the following dialog box appears:
Select how you want to aggregate the field, and then click Next.
In the subsequent dialog box, you're given the option to create four types of quantitative filters:
Range of Values: Select the Range of Values option to specify the minimum and maximum values of the range to include in the view. The values you specify are included in the range.
At Least: Select the At Least option to include all values that are greater than or equal to a specified minimum value. This type of filter is useful when the data changes often so specifying an upper limit may not be possible.
At Most: Select the At Most option to include all values that are less than or equal to a specified maximum value. This type of filter is useful when the data changes often so specifying a lower limit may not be possible.
Special: Select the Special option to filter on Null values. Include only Null values, Non-null values, or All Values.
When you drag a date field from the Data pane to the Filters shelf in Tableau Desktop, the following Filter Field dialog box appears like this.You can select whether you want to filter on a relative date; filter between a range of dates; or select discrete dates or individual dates to filter from the view.
Filter relative dates: Click Relative dates to define a range of dates that updates based on the date and time you open the view. For example, you may want to see Year to Date sales, all records from the past 30 days, or bugs closed last week. Relative date filters can also be relative to a specific anchor date rather than today.
Filter a range of dates: Select Range of dates to define a fixed range of dates to filter. For example, you may want to see all orders placed between March 1, 2009 and June 12, 2009.
Filter discrete dates: Select a discrete date value in the dialog box if you want to include entire date levels. For example, if you select Quarters, you can choose to filter specific quarters (e.g. Q1, Q2, Q3, Q4) from your view, regardless of the year.
The color legend can either be categorical or quantitative. A categorical legend represents discrete categories such as customer names and regions while a quantitative legend represents a range of numeric values such as sales and profit.
This is a legend that shows Provider speciality in a hospital's data set.
Each color represents corresponding provider speciality in the hospital.
Null values represented by green color, can be excluded using filter.
The Pages shelf lets you break a view into a series of pages so you can better analyze how a specific field affects the rest of the data in a view. When you place a dimension on the Pages shelf you are adding a new row for each member in the dimension.
How to create a motion chart
In this chart WEEK(Discharge Date) dragged to Pages and to the Columns.Right click Discharge Date we get the option to select week, month or year.Select week from the Dropdown list.The sum of Length of stay to the Rows.Right click Length of stay, select measure and select sum from the list.
Select circle from the dropdown list in Marks.We can see right side there came the weeks of Discharge Date as soon as you dragged WEEK(Discharge Date) to pages.To view motion chart click play button.
Here Week(Discharge Date) is plotted against the Sum of Length of stay.Checklist the tick mark left to Show history.Click on show history dropdown,this window will open .In this window,Marks to show history you have to select All.The Show field you have to take both option to get Marks and Trails.You can press play button to see.You can pause the motion chart.
Hope you all got basic idea about Tableau prerequisites and visualisation-Bar chart and Motion chart
Learning the fundamental features of tableau is essential .You can learn more about the visualizations in the coming blogs.