Alberto Lusoli
January 13, 2021
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# Tableau study group - 2

January 13, 2021

## Transcript

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7. ### Unioning is a method for appending values (that is, rows)

to tables. You can union tables if they have the same columns. Typical use case: longitudinal research with periodic data updates

9. ### Joining is a method for combining tables related by common

fields (that is, common columns). The result of combining data using a join is a virtual table that extends horizontally by adding columns of data.

11. ### CONDITIONS Fields must have the same format (INT<>INT ; STRING

<> STRING ; etc.) Fields must contain the same values
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15. ### What is a Measure Measures are usually metrics, or numerical

data, like shipping cost. Inside of Tableau, measures are aggregations – they’re aggregated up to the granularity set by the dimensions in the view. The value of a measure therefore depends on the context of the dimensions. Number of records is a Measure automatically created by Tableau
16. ### What is a Dimension Dimensions are usually categorical fields. Specifically,

in Tableau, dimensions set the granularity, or the level of detail in the view. We typically want to group our data by some combination of categories. What dimensions we use to build the view will determine how many marks we have My measure is… …aggregated by Year. Year is a Dimension and it’s a Numerical variable

18. ### Discrete and continuous pills Most of the time, dimensions are

discrete and measures are continuous. However, this isn’t always true. It’s possible to have a numerical dimension be continuous, or to convert a measure to discrete.
19. ### Discrete and continuous pills When a continuous pill is brought

into the view, it creates an axis. This will automatically fill the entire view along that direction.
20. ### Discrete and continuous pills When a discrete pill is brought

into the view, it creates a label with panes for each value. This will take up as much or as little room as required.
21. ### Tableau’s defaults If a field has values that are numbers

that can be added, averaged, or otherwise aggregated, Tableau assigns that field to the Measures area of the Data pane when you first connect to a data source. Tableau is assuming that the values are continuous.
22. ### Tableau’s defaults Therefore, Tableau displays an axis when you drag

a continuous field to Rows or Columns.
23. ### Tableau’s defaults If a field contains values that are names,

dates, or geographical locations—anything other than numbers—Tableau assigns that field to the Dimensions area of the Data pane when you first connect to a data source. Tableau treats the values as discrete. (however, postal codes are an exception. That’s why it is important to double check all measures and dimensions)
24. ### Tableau’s defaults Tableau creates headers when you drag a discrete

field to Columns or Rows. The individual values for a discrete field become the row or column headings. Because these types of values are never aggregated, no new field values are created as you work with your view, so there is no need for an axis.
25. ### Tentative outline 1. Intro to Tableau 1. Installing the software

2. Data sources and reshaping CSV data 3. Tinkering 2. Fundamental concepts I 1. Data – Worksheet – Dashboards – Stories 2. Dimensions and Measures 3. File formats 4. Data manipulation: join, union, blend 5. Fields operations: split, pivot, filter, clean, calculated fields 6. Tinkering 3. Tableau in action 1. Basic visualizations 2. Calculations (Ad hoc calculations, Calculation editor, Table Calculations, ) 3. Data management: extract, live, refresh 4. Tinkering 4. … 5. Dashboards and Stories