protovis part 4: external data and animated labels

Introduction

Now that you have mastered the basics of Protovis, it's time to learn how to load data from an external data file. Using external data has two obvious benefits. First, it simplifies the code, making it easier to work with. Second, the data can be updated without having to rework the code on a page.

We'll work with a JSON file. JSON stands for JavaScript Object Notation. It's similar to XML but it's simpler and results in a smaller file. It's very common on the Web and often times you can get JSON files directly from government sources.

This tutorial also demonstrates how to animate a bar chart and it's corresponding labels to allow readers deeper access to your data.

Filed under: Data Visualization