Grouped Bar Chart

This grouped bar chart is constructed from a CSV file storing the populations of different states by age group. The chart employs conventional margins and a number of D3 features:

• d3.csv - load and parse data
• d3.scale.ordinal - x-position encoding and color encoding
• d3.scale.linear - y-position encoding
• d3.format - SI prefix formatting (e.g., “10M” for 10,000,000)
• d3.max - compute domains
• d3.keys - compute column names
• d3.svg.axis - display axes