Charts & Graphs

A resource for working with Charts and graphs. Mostly a compendium of libraries and third party integrations.

Google Charts

docs: https://developers.google.com/chart/interactive/docs/index 
examples: https://developers.google.com/chart/interactive/docs/gallery

Charts.js

6 chart types
nice animations; very tin js, leverages HTML5 canvas + cross platform fallback 

project: http://www.chartjs.org 
code: https://github.com/nnnick/Chart.js 
docs: http://www.chartjs.org/docs/
examples:  

D3

good for inventing things

project: http://d3js.org 
code: https://github.com/mbostock/d3
drupal module: https://www.drupal.org/project/d3 
API: https://github.com/mbostock/d3/wiki/API-Reference
examples: https://github.com/mbostock/d3/wiki/Gallery

High Charts

free for non-profits
supports line, spline, area, areaspline, column, bar, pie, scatter, angular gauges, arearange, areasplinerange, columnrange and polar chart
also maps with touch support.

 Highcharts has recently put a lot of work into making their charts more accessible!

project: http://www.highcharts.com 
drupal module: https://www.drupal.org/project/highcharts
    https://www.drupal.org/project/charts
code: 
https://github.com/highslide-software/highcharts.com 
docs: http://www.highcharts.com/docs 
examples: http://www.vitalsigns.mtc.ca.gov/transit-ridership#chart-2
    http://www.highcharts.com/demo
    http://www.highcharts.com/maps/demo 

Charts.module

A drupal module with API that supports High Charts and Google Charts libraries. Views integration

project/
code: https://www.drupal.org/project/charts 
docs: https://www.drupal.org/node/2423033 + https://www.drupal.org/node/233753 

Resources

 http://www.sitepoint.com/15-best-javascript-charting-libraries/