Power BI; Data Visualization Tool.

Data Visualization is defined as the pictorial representation of the data to communicate data or information to decision-makers as text data might not be able to reveal the pattern or trends needed to communicate the message.

Why?

According to the writers of A Tour Through the Visualization Zoo, “The goal of visualization is to aid our understanding of data by leveraging the human visual system’s highly-tuned ability to see patterns, spot trends, and identify outliers”, in summary Data visualization makes the data more natural for the human mind to comprehend.

why visualization diagram image

5 Steps of Data Analysis

  • Extract
  • Clean
  • Explore
  • Analyze
  • Share

Data Visualization Tool

Data Visualization tool is a software which provides the accessible way to see and understand trends, outliers and patterns in data. Examples of visualization tools are matplotlib, Tableau, and Microsoft power BI etc. Tableau seemed easier to use compared to power BI;which will be our main focus in this article.

Power BI(Business Intelligence).

According to Microsoft, Power BI is a collection of software services, apps, and connectors that work together to turn your unrelated sources of data into coherent, visually immersive, and interactive insights.

Versions of of Power BI.

  • Power BI desktop: It is a free application you install on your computer that serves as the complete report authoring tool to create reports. It includes powerful features, like the Query Editor.
  • Power BI service:It is an Internet-run program with components stored online with some (or all) processes executed in the cloud, that enables anyone to visualize and analyze data with greater speed, efficiency, and understanding. It is mainly for sharing and distributing reports.
  • Power BI Pro: Paid per-user license, needed to get access to advanced features and the ability to share reports
  • Power BI Premium: Licenses by scale, intended for large businesses and enterprises
  • Power BI Mobile: It is a device-based app for phones and tables
  • Power BI Embedded: A white-label version of Power BI which Independent Software Vendors can embed in their own apps, rather than build their own analytical features
  • Power BI Report Server: An on-premise version of the Power BI Desktop app for businesses that need to keep their data and reports on their own

Components of Power BI.

  • Power Query: It’s a data connection tool that lets you transform, combine, and enhance data from several sources.
  • Power Pivot: It’s a data modeling tool for creating data models.
  • Power View:It’s a data visualization tool that generates interactive charts, graphs, maps, and other visuals.
  • Power Map: It’s a visualization tool for creating immersive 3D visuals
  • Power Q&A:It’s a question and answer engine that lets you ask questions about your data in plain language.

Power BI interface

There are three data interface accessible to power BI users, these views can be selected by clicking one of the three icons on the left side of the power BI:

Image showing the Filter, Visualization and Field Pane.

Filter pane

This automatically appears once a visual is included on the report canvas. Here you can configure which filter to include and then update existing filter to aid your visualization by dragging other fields of interest into the filter pane. One can also rename,sort, format, hide etc .

  • Page-level filters: Its applied on selected page.
  • Report-level filters: Its applied on the entire plot.

Visualization pane

From the image above we can see the visualization pane next to the filter pane.This pane exhibits the different ways one can give insights to their readers or viewers. Visualizations can be edited with the aid of a paint roller.

  • Clustered bar and Column chart: It includes a multiple bar representing values located next to each other. Below is an image of a column clustered chart.
Clustered column chart
100% stacked bar image
Line clustered chart
Table, card and slicer visualization image.
  • Details of a visualization can be seen when we hover our mouse above the current visuals.
  • The formatting tool that looks like a paint roller can be used to change the size of the font of a visualization title.
  • To change the theme of the report ,click the visual currently on the canvas > click view in the ribbon above your desktop.
  • In situations where we have an hierachy in our visuals like, year> quarterhalf >month> date, we drill down with the aid of an arrow like icon around the visual canvas.
A hierachy visualization
  • The second arrow pointing down: drills down one field at a time.
  • The third one with a twin arrow pointing down; drills down on all field at ones.
  • The fourth one which looks like a fork teeth: expands all field at a time.

2. Data view

This view shows the data in your report in data model format, where you can add measures, create new tables ,create new columns, and manage relationships. In the image below we can see the yellow band on the second icon along the left side of the power BI desktop.

Data view image

More on DAX function

  • Creating calculation columns is based on other columns from any table. Any column created is calculated at Data load or when the data is refreshed. A calculated column adds a new column to a table and and evaluates a row
  • Creating calculation tables is the same as columns.
  • Creating calculation measures helps define complex measure to be used on your data. measures are calculated during query time therefore making it efficient because the measure isn’t run everytime the table is accessed unless when it’s used. A measure aggregates multiple rows and result in another field which can be added to a visualization.
  • When defining a calculation column, table or measure, you need to give it a name, followed by an equal sign.
  • When using DAX formula first put the name of the column|table|measures of the new calculation and equal sign then proceed with your preferred function.
  • There is a function called Nested function , it is a function within a function i.e FUNCTION 1(FUNCTION 2(column name)). For example if i want to convert a text of a particular funtion to lowercase, I’ll be making use of the LOWER() function, which converts text to all lowercase. e.g LOWER(FUNCTION 2(column name)).
  • Quick measure tool is that tool one can use to create measure without using DAX functions .They work by providing a menu commonly used divided into 6 categories which are:
Image of a model view

Bsc. Mechatronics Engineering || Budding Data scientist