Gain insights into D3.js fundamentals, explore DOM manipulation, data binding, and SVG. Learn about creating maps, graphs, and network visualizations to master data-driven documentation.

Introduction to Visualization Using D3.js.png

In this course, you will learn the fundamentals of D3.js (stands for Data-Driven Documents), which is a JavaScript library mainly used for visualization.

In the first half of the course, you will cover DOM (Document Object Model) manipulation, method chaining, data binding, and data loading.

In the second half, you’ll cover visualization concepts and dive deep into SVG which is used to draw different geometrical shapes. After that, you’ll work with various maps and graphs in order to display your data. Lastly, you’ll learn about network visualization with the help of nodes and links.

By the end of this course, you will have a new, powerful data visualization library at your disposal.

Introduction to Visualization Using D3.js

<!DOCTYPE html>
<meta charset="utf-8" />
<script src="https://d3js.org/d3.v4.min.js"></script>
<body></body>


codemirror

## Explanation
As shown in the above code:
- **Line 45-49**: We have defined a tooltip with the text `tooltip` in it, and we have made it hidden until some event occurs.
- **Line 73-78**: We have defined two event listeners, `mouseover` and `mouseout`, and every time we hover over the country, a `mouseover` event will occur. We will show the `parent` name of the rectangle, which, in this case, is the name of the continent. We will also make it visible. When we leave the rectangle, the `mouseout` event will occur and will make the tooltip hidden again. 

# Explanation
As shown in the above code:
- **Line 45-49**: We have defined a tooltip with the text `tooltip` in it, and we have made it hidden until some event occurs.
- **Line 73-78**: We have defined two event listeners, `mouseover` and `mouseout`, and every time we hover over the country, a `mouseover` event will occur. We will show the `parent` name of the rectangle, which, in this case, is the name of the continent. We will also make it visible. When we leave the rectangle, the `mouseout` event will occur and will make the tooltip hidden again. 

This review provides a detailed analysis to solve the 'Add Tooltip to a Treemap' challenge.

Introduction

D3.js Fundamentals

Scales

Drawing Basic Shapes

Chart Fundamentals

Network Visualization, Hierarchical Data, and Interactivity

Conclusion

Solution Review: Add Tooltip to a Treemap

Solution

Explanation