Midterm lecture 1 study guide

Question 1

definition, purpose and use cases of data visualization

Answer 1

• Definition: The representation of data through visuals
• Purpose: to analyze, and reveal patterns and insights from data
• Use cases:
  1. record
  2. reveal and analyze patterns, trends and support reasoning
  3. confirm a hyp. about the data
  4. communicate findings

Question 2

• charles minard:
• Edward tufte:
• william playfair:
• stephen phew:
• claudius ptolemy:
• john medina
• jacob bronowski

Answer 2

John medina- neuroscientist who made the claim that 65% of visual data could be remembered three days later vs. only 10% of textual information

Jacob bronowski-established the concept of triangle of forces which shape a visual design and it’s effectiveness

• material object is made out of
• actions to make the object
• purpose of the object

As each of these changes others have to change to accomodate for it

Edward tufte- Early author of data visualization, advocate of minimal graphics and unecessary chart junk»more analysis

Charles minard (1800’s)-created visuals that were great for storytelling but not so much for analysis. Also created pie chart distribution of cattle consumption over provinces graph, napolean’s myriad, and hannibal

William playfair: founder of graphical statistics

• pie chart
• bar chart
• line graph

stephen phew-predominant researcher in the area of data visualization

John tukey-wrote wrote about exploratory data analysis and practiced representing data through visuals. He created the

• box and whisker plot
• pareto diagram
• scatterplot
• histogram

Jaques bertin: provided fundamental knowledge about

• color
• shapes and size
• perception

Question 3

Definitions and difference between business intelligence and discovery (3v’s), big data, and why we use data visualization in the big era:

Answer 3

1. Business intelligence and discovery: Analyze data uncover patterns and trends and use them to predict the future (what we currently do)
2. Big data can be broken down into three categories:
3. volume-amount of data stored on websites, cloud computing systems and hardware (ex: facebook stores over 40 billion user photos)
4. veracity-type of data (audio, visual, telemetry, behavioral, performance)
5. velocity-speed at which data is produced(now able to produce very quickly and store in a cheap manner)

Question 4

three categories of data visualization:

Answer 4

• Three forms of data visualization:
  1. exploratory: messy visuals meant for analysts to derive insights and patterns from
  2. explanatory: Visuals meant to answer a question or prove a point with or without narration. Clean, simple easy to follow along and understand.
  3. Hybrid: offer a controlled set of interactive visuals meant to reveal to the audience a specific set of findings. Ex: Choose your own adventure»click on safari»choice between gori

Question 5

visual concepts:

• visual memory
• picture superiority effect
• visual thinking/visual queries
• saccadic eye movement

Answer 5

• Visual memory: This a lot more powerful than textual memory. It stays in your mind for a lot longer time
• picture superiority effect: demonstrates that 65% of visuals are retained after 3 days vs. 10% of textual information
• visual thinking/visual queries-Using visuals to uncover patterns using those patterns to draw conclusions. The more clear a data visualization is the faster the process is.
• saccadic eye movement-this is the pattern your eyes follow to track information when observing a data visual or a dashboard.

Question 6

importance of color in visualization and how to use it in visualizing data

Answer 6

-Color helps emphasize, draw attention to and establish meaning in data. You should limit your visualization to 2 or 3 colors including gray and use blue orange instead of red and green for highlight, alert colors.

Question 7

perceptual popout
identify popout channels
gestalt principals

Answer 7

Perceptual popout: what standout to people the most in a visualization
popout channels:
1. spatial grouping
2. elongation
3. movement
4. color
5. shapes
6. orientation
7. elongation
8.hue-a color or shade

Gestalt principles: The brain’s tendency to complete patterns that it sees in visuals. As a result shapes with spaces in them will appear to be filled, and groups of certain colors or shapes will appear more than others because of the brain’s desire to group certain information, together based on the colors it sees first and the formulate patterns which lead to incorrect conclusions.

Question 8

Impact of visual illusions in data visualizations:

• visual memory
• picture superiority effect
• visual thinking/visual queries
• saccadic eye movement
• top and bottom down movement

Answer 8

visual memory: memory that sticks in your mind much longer than textual memory

picture superority effect: states that you will remember 65% of a visual vs. only 10% of textual information.

visual thinking/visual queries: are used to find patterns in things which affect how we process cognitive information. The goal of data visualization is to make sure that these queries are processed very quickly: should be able to find patterns and jump to a conclusion very quickly.

saccadic eye movement: Refers to the way the human eye views information. Dashboards and data visuals are used based on this.

Top and bottom down movement:

1. Top down: when you have a problem and you are trying to find a solution by analyzing the information, from your organization, outside info and data
2. bottom down: you are trying to find out what the problem might be by analyzing information within your organization, outside of your organization and data.

Question 9

Basic charts-

1. Bullet graph
2. symbol graph
3. chloropleth
4. Gantt chart
5. Heat map
6. Highlight table
7. Line chart
8. Scatterplot
9. Histogram
10. Stacked bar chart
11. Tree map

Answer 9

Bullet graph: uses length, height and position to show a difference between the target value and the actual value

stacked bar chart: represents data using length and height and portion of whole filled

tree map-used to categorize a wide amount of data and diffrentiates based on size and color

Question 10

know the impact of visual illusions and how to identify their effects

Answer 10

Herman effect-dots appear as an after effect between small gaps between shapes that may distract a viewer. The best way to control this is by seperating the shapes by as far as possible.

Moire effect: When there is too much information on a page this may cause the viewer difficulty in diffrentiating between the different types of data on screen. The best way to control this is by eliminating chart junk

Question 11

Evolution of data visualization

Answer 11

1. Warehouse storage(80-90’s): collecting and storing data
2. Business intelligence (90’s 2000): analyzing past and see what trends in the data has led to present day data
3. Performance managment (2005-): using present data to make changes in the future
4. Business intelligence and discovery(2010): using present data to predict future trends

Question 12

How visual hierarchy impacts dashboard design for business audiences

Answer 12

visual hierachy refers to the way elements are arranged on a screen so that the viewer can see the most important information first and the least important information last.

Dashboards are designed so that the most important information is in the upper left corner and the least important information is in the bottom right corner.

Question 13

Difference between visualization used for analysis verses presentation

Difference between visualization used for dashboards and stories

Answer 13

• Analysis: to derive patterns and insights from data
• Presentation: impact the visualization has on the audience does it keep them engaged and interested and understand what you are trying to get across

Visualization used for dashboards: data analysis

Visualization used for stories: meant to capture attention and give a basic explanation of data to the general audience.