Preparing a Graph:
When preparing a graph to represent data there are two options— the line graph or the chart. A line graph is useful for representing continuous data and the key to presenting a successful line graph is to keep the design simple. When drawing two curves to be compared, use one varying symbol to distinguish the two and label them directly. The axis of the line graph must labeled and be proportional to each other in a 1:1 or 3:2 ratio so as not to mislead your readers.
If you are looking to illustrate discrete units of information a column chart is a good choice. When comparing groups using a column chart keep the maximum number to two or three groups, otherwise the chart may become confusing and hard to read. If you find you have many columns, rather that make your graph looked cramp use a bar chart.
To give more information about individuals in your data set individuals can be displayed as dots as an opened ended column chart.
Another option to display your data is the box-and-whisker plot or pie charts.
Tufte: Graphical Excellence
Graphical Excellence, according to Tufte, presents intriguing data clearly and efficiently. The data presented should give “the viewer the greatest number of ideas in the shortest time with the least ink in the smallest space”—efficiency. Tufte points out that the graphics used to represent the data will only be as valuable as the information it is representing. He describes several different types of graphics that are used to display data: Data Maps, Time-Series, Narrative Graphs of Time and Space, and Relational Graphics. Data Maps use geographical maps to represent information about different regions, for example cancer rates in all the districts across the United States. Time-Series graphics have a dimension that follows a measurement of time, such as weather patterns over the course of a year. Narrative Graphics of Space and Time enhance Time-Series graphics by depicting the data progressing over space and time. The example Tufte uses for this particular kind of graphic is Charles Joseph Minard’s graph of Napoleon’s army’s diminishing numbers as it progressed through Russian territory in its’ failed campaign.
Overall I learned that simplicity and efficiency are the key to creating effective visuals. I believe that once we start to make our own graphs we will be able to learn more from these readings.
Tufte (Chapter 1-Principles of Graphic Excellence)
In chapter one, Tufte lays his main focus on the various techniques of visualizing data effectively. According to him, “graphical displays would be effective only if the viewer begins thinking about the substance (data) itself, rather than the graphical design or methodology used for presenting the data.” Given that the data obtained is accurate, displaying the data effectively to the audience would be one topic that would pose a problem. The three main types of graphical visual that Tufte discusses are: Data Maps, Time-Series Plots and Relational Graphics. Data Maps are geographical maps that can carry a large volume of data in a small space. A Time-Series Plot would be used to display the time variation of data sets, associated with observation points. Relational Graphics are used mainly to depict a large quantity of multivariate data.
Tufte concludes by saying that, the effectiveness can be measured only by the clarity, precision and efficiency of the ideas, the number of ideas given to the viewer within the shortest amount of time, variation of the data, and lastly, the reliability of the data.
Gustavii (Chapter 5-Preparing a graph)
Gustavii, in chapter 5, discusses about the various ways of representing a graph. The two graphs he mainly focused on are: the line graph and the chart. Line graphs are mainly used to represent continuous and simple data sets. On the other hand, a column chart (also known as a bar chart) is used when representing new data sets that have no continuity. Gustavii also mentions of the importance of correct labeling of the graph.
While both the authors talk about the different techniques that may used to represent data, Tufte and Gustavii, state that simplicity is the key to delivering a complex yet effective data representation.