Defining a new chart

Creating the chart library file

Under the directory charts, create a new Javascript file, ex. donut.js.
In this file, you should place the functions used to take a generic data set and render a chart of the specific format. A function should be created with a controller function of the format:
function donut(data, centerLabel, sel, w, h) {
where

• data is a multi-dimensional array with headers
• centerLabel should be a string with the title of the chart
• sel should contain the selector to place the chart into
• w and h should contain the width and height respectively for the chart to be rendered.

Creating an the chart index definition

In educhart.js, the charts object is defined in the init function. Each chart needs to have several key properties.

• map: function that performs a map of a particular data set to another
  Example: to map years in data set A to a value in B
• scale: function to scale a data set to the bound defined for a chart
  Example: scale values to percentages
• add: add data to a data set
  Example: calculate averages for each row and place in a new column.
• create: function to create the chart which should taking simple inputs.