# Creating Meaningful Visualizations | ](../../sketchnotes/13-MeaningfulViz.png)| |:---:| | Meaningful Visualizations - _Sketchnote by [@nitya](https://twitter.com/nitya)_ | > "If you torture the data long enough, it will confess to anything" -- [Ronald Coase](https://en.wikiquote.org/wiki/Ronald_Coase) One of the essential skills for a data scientist is the ability to create meaningful data visualizations that help answer specific questions. Before visualizing your data, you need to ensure it has been cleaned and prepared, as covered in previous lessons. Once that's done, you can start deciding how best to present the data. In this lesson, you will explore: 1. How to select the appropriate chart type 2. How to avoid misleading visualizations 3. How to use color effectively 4. How to style charts for better readability 5. How to create animated or 3D visualizations 6. How to design creative visualizations ## [Pre-Lecture Quiz](https://purple-hill-04aebfb03.1.azurestaticapps.net/quiz/24) ## Selecting the appropriate chart type In earlier lessons, you experimented with creating various types of data visualizations using Matplotlib and Seaborn. Generally, you can choose the [appropriate chart type](https://chartio.com/learn/charts/how-to-select-a-data-vizualization/) based on the question you're trying to answer using the following table: | Task | Recommended Chart Type | | -------------------------- | ------------------------------- | | Show data trends over time | Line | | Compare categories | Bar, Pie | | Compare totals | Pie, Stacked Bar | | Show relationships | Scatter, Line, Facet, Dual Line | | Show distributions | Scatter, Histogram, Box | | Show proportions | Pie, Donut, Waffle | > ✅ Depending on the structure of your data, you may need to convert it from text to numeric format to make certain charts work. ## Avoiding misleading visualizations Even when a data scientist carefully selects the right chart for the data, there are still ways to present data in a misleading manner, often to support a specific narrative at the expense of accuracy. There are numerous examples of deceptive charts and infographics! [](https://www.youtube.com/watch?v=oX74Nge8Wkw "How charts lie") > 🎥 Click the image above to watch a conference talk about misleading charts. This chart flips the X-axis to present the opposite of the truth based on dates:  [This chart](https://media.firstcoastnews.com/assets/WTLV/images/170ae16f-4643-438f-b689-50d66ca6a8d8/170ae16f-4643-438f-b689-50d66ca6a8d8_1140x641.jpg) is even more misleading. At first glance, it appears that COVID cases have declined over time in various counties. However, upon closer inspection, the dates have been rearranged to create a deceptive downward trend.  This infamous example uses both color and a flipped Y-axis to mislead viewers. Instead of showing that gun deaths increased after the passage of gun-friendly legislation, the chart tricks the eye into believing the opposite:  This peculiar chart manipulates proportions to a comical degree:  Another deceptive tactic is comparing things that are not truly comparable. A [fascinating website](https://tylervigen.com/spurious-correlations) showcases 'spurious correlations,' such as the divorce rate in Maine being linked to margarine consumption. A Reddit group also collects [examples of poor data usage](https://www.reddit.com/r/dataisugly/top/?t=all). Understanding how easily the eye can be tricked by misleading charts is crucial. Even with good intentions, a poorly chosen chart type—like a pie chart with too many categories—can lead to confusion. ## Using color effectively The 'Florida gun violence' chart above demonstrates how color can add another layer of meaning to visualizations. Libraries like Matplotlib and Seaborn come with pre-designed color palettes, but if you're creating a chart manually, it's worth studying [color theory](https://colormatters.com/color-and-design/basic-color-theory). > ✅ Keep accessibility in mind when designing charts. Some users may be colorblind—does your chart work well for those with visual impairments? Be cautious when selecting colors for your chart, as they can convey unintended meanings. For example, the 'pink ladies' in the 'height' chart above add a gendered implication that makes the chart even more bizarre. While [color meanings](https://colormatters.com/color-symbolism/the-meanings-of-colors) can vary across cultures and change depending on the shade, general associations include: | Color | Meaning | | ------ | ------------------- | | red | power | | blue | trust, loyalty | | yellow | happiness, caution | | green | ecology, luck, envy | | purple | happiness | | orange | vibrance | If you're tasked with creating a chart with custom colors, ensure that your choices align with the intended message and that the chart remains accessible. ## Styling charts for better readability Charts lose their value if they are difficult to read. Take time to adjust the width and height of your chart to ensure it scales well with your data. For example, if you need to display all 50 states, consider showing them vertically on the Y-axis to avoid horizontal scrolling. Label your axes, include a legend if necessary, and provide tooltips for better data comprehension. If your data includes verbose text on the X-axis, you can angle the text for improved readability. [Matplotlib](https://matplotlib.org/stable/tutorials/toolkits/mplot3d.html) also supports 3D plotting if your data warrants it. Advanced visualizations can be created using `mpl_toolkits.mplot3d`.  ## Animation and 3D visualizations Some of the most engaging visualizations today are animated. Shirley Wu has created stunning examples using D3, such as '[film flowers](http://bl.ocks.org/sxywu/raw/d612c6c653fb8b4d7ff3d422be164a5d/),' where each flower represents a movie. Another example is 'Bussed Out,' an interactive experience for the Guardian that combines visualizations with Greensock and D3, along with a scrollytelling article format, to illustrate how NYC addresses homelessness by bussing people out of the city.  > "Bussed Out: How America Moves its Homeless" from [the Guardian](https://www.theguardian.com/us-news/ng-interactive/2017/dec/20/bussed-out-america-moves-homeless-people-country-study). Visualizations by Nadieh Bremer & Shirley Wu While this lesson doesn't delve deeply into these powerful visualization libraries, you can experiment with D3 in a Vue.js app to create an animated visualization of the book "Dangerous Liaisons" as a social network. > "Les Liaisons Dangereuses" is an epistolary novel, presented as a series of letters. Written in 1782 by Choderlos de Laclos, it tells the story of the morally corrupt social maneuvers of two French aristocrats, the Vicomte de Valmont and the Marquise de Merteuil. Both meet their downfall, but not before causing significant social damage. The novel unfolds through letters written to various individuals in their circles, plotting revenge or simply creating chaos. Create a visualization of these letters to identify the key players in the narrative. You will complete a web app that displays an animated view of this social network. It uses a library designed to create a [network visualization](https://github.com/emiliorizzo/vue-d3-network) with Vue.js and D3. Once the app is running, you can drag nodes around the screen to rearrange the data.  ## Project: Build a network chart using D3.js > This lesson folder includes a `solution` folder with the completed project for reference. 1. Follow the instructions in the README.md file located in the starter folder's root. Ensure you have NPM and Node.js installed on your machine before setting up the project's dependencies. 2. Open the `starter/src` folder. Inside, you'll find an `assets` folder containing a .json file with all the letters from the novel, annotated with 'to' and 'from' fields. 3. Complete the code in `components/Nodes.vue` to enable the visualization. Locate the method called `createLinks()` and add the following nested loop. Loop through the .json object to extract the 'to' and 'from' data for the letters and build the `links` object for the visualization library: ```javascript //loop through letters let f = 0; let t = 0; for (var i = 0; i < letters.length; i++) { for (var j = 0; j < characters.length; j++) { if (characters[j] == letters[i].from) { f = j; } if (characters[j] == letters[i].to) { t = j; } } this.links.push({ sid: f, tid: t }); } ``` Run your app from the terminal (npm run serve) and enjoy the visualization! ## 🚀 Challenge Explore the internet to find examples of misleading visualizations. How does the author mislead the audience, and is it intentional? Try correcting the visualizations to show how they should appear. ## [Post-Lecture Quiz](https://purple-hill-04aebfb03.1.azurestaticapps.net/quiz/25) ## Review & Self Study Here are some articles about misleading data visualizations: https://gizmodo.com/how-to-lie-with-data-visualization-1563576606 http://ixd.prattsi.org/2017/12/visual-lies-usability-in-deceptive-data-visualizations/ Explore these interesting visualizations of historical assets and artifacts: https://handbook.pubpub.org/ Read this article on how animation can enhance visualizations: https://medium.com/@EvanSinar/use-animation-to-supercharge-data-visualization-cd905a882ad4 ## Assignment [Create your own custom visualization](assignment.md) --- **Disclaimer**: This document has been translated using the AI translation service [Co-op Translator](https://github.com/Azure/co-op-translator). While we aim for accuracy, please note that automated translations may include errors or inaccuracies. The original document in its native language should be regarded as the authoritative source. For critical information, professional human translation is advised. We are not responsible for any misunderstandings or misinterpretations resulting from the use of this translation.