Introduction to Data Visualisation and Analysis with PowerBI

Video Playlist https://www.youtube.com/watch?v=WM_sS72xGXg&list=PLUIkYG_TQD7wkDrK7L8P7XnLPIl_G7Ugv

Presentation to accompany the training videos https://github.com/stretcharm/PowerBI_Training/blob/master/DataViz%20And%20Analysis%20PowerBI%20Session.pptx

• Start PowerBI Desktop
• Visualisation & Fields Panes
• Toolbar
• Help and Support Links
• Preview Features

https://github.com/stretcharm/PowerBI_Training/blob/master/Uk%20Tourism_Exercise%20Video%201-4.pbix

• Links to web pages to get the sample data
• https://www.visitbritain.org/inbound-tourism-trends
• https://www.ons.gov.uk/peoplepopulationandcommunity/leisureandtourism/datasets/monthlyoverseastravelandtourismreferencetables
• https://www.ofx.com/en-gb/forex-news/historical-exchange-rates/monthly-average-rates/

https://github.com/stretcharm/PowerBI_Training/blob/master/Uk%20Tourism_Exercise%20Video%201-4.pbix

• Get Data
• From Start of Home Toolbar
  • Lots of data source types supported.
• Open Csv/text
  • Sample Data provided change delimiter
  • Load or Edit
• Query Editor allows you to change the data after it's loaded
  • Close and Apply
• Drag and drop fields to background to add a couple of quick visuals
• Visuals try to guess what the best type is for the data e.g map for countries
  • Cross highlighting

https://github.com/stretcharm/PowerBI_Training/blob/master/Uk%20Tourism_Exercise%20Video%201-4.pbix

• Save the Document
• We can search for fields
  • Fields have indicators for different types e.g. Date, Summary, Measure, Calculated Column, Geolocation
• Change visuals
  • Click and then select a different visualisation
• Edit Query
  • Opens Query Editor Window
• Name our Query( or File we loaded)
• CSV type uses headers from the file
• Rename Columns
  • F2 or Right mouse rename
• Bar under name gives simple profile data
• Column Dropdown to see list and filter
• Lots of toolbar or menu option to help you manipulate you data

End File https://github.com/stretcharm/PowerBI_Training/blob/master/Uk%20Tourism_Exercise%20Video%201-4.pbix

• Extract Month into a new Column

• Formula bar

• Column from example

  • Select columns
  • Enter the Answer in the new Column
  • PowerBI tries to create the code to get you this for all other rows
  • Change name

• Change types

  • Try to keep types correct as it can give you problems
  • if a field is not a date or number and you want to to behave like one

• Apply

  • Powerbi loads the data and then apply all the changes we make
  • If we change the source then it will reapply the steps we added

• Date field shows with data icon and automatically adds a hierarchy

• Add date based line/bar

• visuals understand the hierarchy

  • Icons/Right Mouse for drill in/out, expand or go up/down a level
  • Data cross filters
  • We can edit the levels on the visual e.g. remove Quarter

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• Move/resize the current visuals
• Copy (Ctrl C) and Paste (Ctrl V)
• Edit the fields used by the visual
• Drag fields onto the visual or the visualisation field lists
• Dragging to background creates a new visual
  • We can also have tables
  • Hover over shows tool tips
• Manually create a hierarchy on some visuals by dragging a column to the axes
• Format pane of the visual has lots of options
  • Visuals also have ... which can control items like sort order
• We can add slices to filter that data
• Treeview help show the size
• Ribbon shows the change by types over time

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• We can resize them using the general to get the same size and use the align options to make the tidy
• Change values to use % calcs and show the data labels
• Add tooltips to visuals
• You can add visuals from the toolbar as well and can overlay one on top of another e.g. Card with a KPI behind a Donut
• Everything still cross highlights

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• We can quickly change the colour scheme using themes either built in or we can create our own
• DAX is the name of the language used to create calculations in PowerBI
• Measures are calculations on our data and can be added from the right menu over the fields or toolbar
• The calcuklate is show in the forumlar bar.
• We can add a calcuation similar to exce like Sum
• Then use in our visuals
• Note: Measures work over the data set unless filtered, but are the same calculation for 1 or a million rows
• Lots of functions just like Excel
• Functions with X at the end calculate on a row by row basis
• They appear in our field list with a different icon
• We can show data behind the visuals if we want to check (or use a table visual)
• There is also an option to make the visuals full screen in the corner if you hover
• DAX can be simple or complex and have multiple lines = In order to get a rank we need to Provide a list of things to rank e.g. Country and a value to rank. We have to use a calculate function get the sum
• Calculate can do very advanced things but here it just provides the total for each country
• We can add multiple pages to our document
• Adding data to a table lets use check the calculation is working correctly
• The Measure works on the data given so if want to see it by year it will calculate the rank on each year
• Visuals can have too much data so we can filter to the Top values
• We can also bin or group data to make it easier to work with on our visuals
• Right Mouse on field and select new group
  • A new field and icon is created for the group/bin
  • We can then use this on an axis
  • We can edit the options to make it suit our needs.
  • PowerBI does this by creating a DAX in the background for us.
• We can also make use of DAX Quick Measures which are prebuilt calculatutions
  • Pick the fields you want and it will create the DAX
  • You can then edit it or just learn how to write more advanced DAX
• Here we can create a calculation that shows the spending differemce from a yearly visit purpose from those spend by visiting friends or Relatives

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• PowerBI provides parameters which are very useful for configuration such as the location of your files
  • We can then use a parameter in our queries
• Excel or file data can provide us with challenges if it has headers of different structures on different rows.
  • Use Get Data or New Source
  • We can pick a Sheet from the excel
  • Rename the Query
  • Make use of our parameter
• Clean up the data removing unwanted rows and getting headers from the top row
  • Rename columns
• The Years are missing on some rows so we can use the Fill Down transformation to fix this
  • We also have blank rows so filter them out using the Month columns
  • Select and remove unwanted columns
  • There are some extra characters in the Month that will cause problems so we can use replace to get rid of them
• Use add column by example to create a date field
• Set types manually or use detect data types, but be careful if there is text and numbers of a column as it doesn't look at all the rows.
• You can reorder columns to make it easier to work with
• Close and Apply
  • We now have a new Query/Table in our field list
• The grid (Data) view shows the rows
• The third view is relationships and can show how our data is linked
• Again we can use the dates and fields to create a visual
• However the data has a column for each value type this can harder to work with. E.g if we had months columns on or spreadsheet we cannot filter them as they are separate fields

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• We start by duplicating our query.
  • This is also useful if you want to try something as there is no undo in the query editor
• If we want to use the results of the first query we could also use reference
• To turn the columns into rows we select the columns we dont want to pivot and then use Unpivot other Rows
  • We now have a row for each type of value
• We can then create the same graph with an Area Legend and filter different areas as required
• This will also cross hightlight/filter

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• Use Get Data and paste the web site
  • We have 2 options use tables if the web site has provided them or using web by example. Web by example tries to fid the data you want from a web site given columns and values you provide
  • If possbile use tables as the data is often more reliable
• Again clean up the data by remoiving unwanted rows renaming fields and setting data types
• Apply and we have a 3rd query/table
• However the dates dont match the other data. How can we fix this?

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• First filter the exchange rates as we don't have an data as our other data is not as old
• Ensure you filter your data as much as possible before loading into PowerBI whilst it can handle very large data sets it will be slower
• If we use a date slicer it only works on a single data set
• As each data set has different grains(the level of detail) we cannot just join the dates. They have more than 1 row per date So to let use connect them we can create special table that just has a list of dates
• I'm going to use DAX for this, but it can be done in many ways Add new Table in Modelling and use the Calendar function
• This creates a row for each date between the ranges I provided
• I can then join the Date to the other tables on the relationship view
• Change the slicer to use this date table and we can now filter the different date together
• We can use similar techniques to join data and build models
• Dax can also be used to calculate measure across data that is joined like this

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https://github.com/stretcharm/PowerBI_Training/blob/master/UK_Tourism_final.pbix