38  Introduction to Data visualization

Data visualization is the graphical representation of information and data. By using visual elements like charts, graphs, and maps, data visualization tools provide an accessible way to see and understand trends, outliers, and patterns in data. Here’s a more detailed look at data visualization, including some common types of visualizations and examples.

38.1 Importance of Data Visualization

  1. Clarity and Efficiency: Data visualization helps to explain facts and determine causes faster than raw data can. This is particularly valuable in a business context, where strategic decisions are based on data insights.

  2. Trend Recognition: Visuals can highlight trends and correlations more effectively than tables of numbers, which in turn can lead to more effective decision-making.

  3. Data-Driven Storytelling: Visuals can be used to narrate a story from the data, making the conveyed messages more engaging and understandable.

38.2 Types of Presentation of Data

  1. Line Graphs: Useful for showing changes over time. For example, a company might use a line graph to track its revenue growth across several quarters.

  2. Bar Charts: Effective for comparing quantities among different groups. For instance, a bar chart could compare the sales performance of different products within a portfolio.

  3. Pie Charts: Suitable for showing percentages or proportions. A market research company might use a pie chart to illustrate the market share of different competitors.

  4. Scatter Plots: Used to identify relationships between variables. For example, an economist might use a scatter plot to analyze the relationship between unemployment rates and economic growth.

  5. Heat Maps: Great for representing the intensity of data. Heat maps could be used to show areas of high activity on a website, or to depict geographic concentrations of a population.

  6. Infographics: Combine various types of visualizations into a single cohesive graphic that tells a story or explains complex data sets succinctly.

38.2.1 Advanced Visualizations

  1. Geographic Maps: Enhanced with layers of data to provide spatial context. These are often used in environmental studies and logistics.

  2. Gantt Charts: Utilized primarily for project management to visualize project schedules, showing the duration of tasks against the progression of time.

  3. Dashboards: Interactive interfaces that dynamically display data and allow users to filter and manipulate information quickly.

38.2.2 Examples of Data Visualization

  • Google Analytics Dashboards: Show web traffic sources, page views, and user engagement metrics across various demographics.

  • Public Health Visualizations: Like those used by the World Health Organization or the Centers for Disease Control and Prevention, to show occurrences of diseases like COVID-19, their spread, and vaccination rates across different regions.

  • Financial Market Charts: Such as those seen on Bloomberg or CNBC, where complex financial data like stock performances, market indices, and economic indicators are updated in real-time.

  • Social Media Insights: Platforms like Facebook and Twitter provide users with detailed charts and graphs on post engagements, audience growth, and activity patterns.


Summary

Concept Description
Foundations
Data Visualization The graphical representation of information and data using charts, graphs and maps
Why Visualize
Clarity and Efficiency Visual encodings convey patterns faster than raw tables, supporting decision-making
Trend Recognition Visuals make trends, outliers and correlations stand out that would be hard to see in tabular form
Data-Driven Storytelling Charts can be sequenced to narrate a finding, making the message memorable and shareable
Common Chart Types
Line Graph Best for showing how a quantity changes over time, such as quarterly revenue
Bar Chart Best for comparing quantities across discrete groups, such as products or regions
Pie Chart Best for showing parts of a whole when there are only a few categories
Scatter Plot Best for identifying relationships between two continuous variables
Heat Map Encodes intensity by colour, useful for spatial concentration or activity matrices
Infographic Combines multiple chart types and annotations into one composite visual story
Advanced Visualisations
Geographic Map A map enriched with data layers to add spatial context to the analysis
Gantt Chart A timeline visualisation widely used to track project schedules and dependencies
Dashboard An interactive interface that lets users filter and explore many charts at once
Examples in Practice
Analytics Dashboards Examples such as Google Analytics that surface traffic, engagement and demographics in one view
Public Health Visualisations Examples such as WHO or CDC dashboards that track disease spread and vaccination coverage
Financial Market Charts Real-time displays of stock prices, indices and economic indicators on services like Bloomberg