Data Visualization Lecture Notes PDF

Data Visualization Dr. Amira Abdelatey AGENDA Overview - Visualization Benefits of visualization Choosing the right chart/graph VISUALIZATION ▪Visualization is the technique for creating images, diagrams, or animations to communicate a message. ▪Data visualizations are a vital component of a...

Data Visualization Dr. Amira Abdelatey AGENDA Overview - Visualization Benefits of visualization Choosing the right chart/graph VISUALIZATION ▪Visualization is the technique for creating images, diagrams, or animations to communicate a message. ▪Data visualizations are a vital component of a data analysis, as they have the capability of summarizing large amounts of data efficiently in a graphical format. ▪Visualization through visual imagery has been an effective way to communicate message. ▪One of the trickiest parts of the analysis process is choosing the right way to represent your data using one of these visualizations. ▪Data visualization helps decision-makers understand difficult concepts or discover new patterns.  STEPS TO DESIGNING AN INFORMATION VISUALIZATION 1. Define the problem: This will require answers to the 5W’s&H question, Who, What, When, Where, Why and How. “Who are my users?”, “What does the user want from this?”, “When are they likely to use this?”, “Where are the users when they do this?” “Why will they use this instead of that?” “How will they do this?” 2. Define the data to be represented: There are three main types of data that can be represented through information visualization. Quantitative data- Ordinal data- categorical data. 3. Define the dimensions required to represent the data: Dimensions has to deal with the number of attributes your data-set has 4. Define the structures of the data: You need to analyse the data format for organizing, storing the data and how they relate with each other. Linear regression is sample relationship structures 5. Define the interaction required from the visualization: Should the user be able to transform or modify data ?”, “ should the user control over the generation of views?”. Static models (cann’t be alterered by the user) - Transformable models (allow the user to vary parameters for analysis) BENEFITS OF VISUALIZATION 1.It helps us to convey the right message to the audience through visuals. 2.It helps us find outliers in our data. 3.It helps the business leader to take an accurate decision. 4.It helps us to understand how the data is distributed over time. IS DATA VISUALIZATION IN DEMAND? ▪It provides greater insight ▪It helps you make data-driven decisions ▪It grabs your audience’s attention ▪It can be repurposed COMMON ROLES FOR DATA VISUALIZATION Comparing values between groups Looking at how data is distributed Showing a part-to-whole composition Observing relationships between variables Showing change over time  MATPLOTLIB LIBRARY Matplotlib is a graph plotting library in python that serves as a visualization utility. MATPLOTLIB LIBRARY SUBPLOT The subplot() function takes three arguments that describes the layout of the figure. *The layout is organized in rows and columns *The third argument represents the index of the current plot.  SUBPLOT plt.subplot(2, 3, 1) plt.plot(x,y) plt.subplot(2, 3, 2) plt.plot(x,y) plt.subplot(2, 3, 3) plt.plot(x,y) plt.subplot(2, 3, 4) plt.plot(x,y) plt.subplot(2, 3, 5) plt.plot(x,y) plt.subplot(2, 3, 6) plt.plot(x,y) Hint: Code not complete PLOT PIE VISUALIZATION MUST PROVIDE MESSAGE YOU MUST ASK 5W&H COMPARISON COMPARE ONE DATA VALUE WITH OTHERS Dot Plots Column Chart Example: - Sales comparison over different regions - Economy rate comparison  TIME SERIES VALUES DISPLAY HOW SOMETHING CHANGED OVER TIME Column Chart Line Chart Column Chart Box Plot (vertical). To feature overall trends A box plot can be useful and patterns and support when a distribution of their comparisons values need to be Example: plotted for each time - Hourly temperature variation over time period - Run rate tracker over by over  PART-TO-WHOLE (COMPOSITION) VALUES REPRESENT PARTS (RATIOS) OF A WHOLE Bar chart Stacked area chart Example: - Revenue distribution by different regions - Run rate tracker over by over  DISTRIBUTION HOW DATA POINTS’ VALUES ARE DISTRIBUTED FOR UNDERSTANDING THE PROPERTIES OF DATA FEATURES. Histogram Box Plots When Comparing Multiple Distributions To show the spread of data values over categorical or continuous values. Example: Box plot for detecting - Distribution of bugs found in 10 weeks of software testing phase. outlier  RELATIONSHIPS HOW RELATIONSHIPS BETWEEN DATA VALUES Scatter plot heatmap Compare between non-numeric values Bubble chart Relation between three variables To show the relationships between two variables. Example: - relationships between working less and being happier Schematics Explain how experiment was conducted or Illustrations design concepts for engineering project Flow Charts OTHER Raw data or statistical VISUALIZATIONS summaries in well- Tables A PICTURE IS WORTH organized manner. Convey important details. A THOUSAND WORDS Great to show Photographs experimental setup, or examples of actual results ADHERE TO DATA PRESENTATION STANDARDS IN YOUR FIELD Expected presentations of data in visualization how is data presented? Are there graphs? What kind? What statistics are used?  Emphasize most important data Orient graphs for legibility ‫الوضوح‬ VISUAL BEST Organize graph/table PRACTICES Avoid overloading graphs Limit # of colors and shapes Inform through important text DATA ANALYSIS VS DATA VISUALIZATION Traditionally enter data into spreadsheet (Excel) Satisfactory, but strengths are in data analysis – not visualization Time consuming to create graph variations Alternative: Use data visualization software FREE to students and teachers with.edu email https://www.tableau.com/academic/teaching