The Open Data Network connects publishers of high-value data to the businesses, developers, and analysts that use, reuse, and enrich data. The members of the network work together to share best practices, adopt standards, and advocate for open data broadly.
Although armed with only six chart types, open source library Chart.js is the perfect data visualization tool for hobbies and small projects. Using HTML 5 canvas elements to render charts, Chart.js creates responsive, flat designs, and is quickly becoming one of the most poplar open-source charting libraries.
Packed with graphs, charts, maps and more Tableau public is a popular data visualization tool that's also completely free. Users can easily drag and drop data into the system and watch it update in real-time, plus they can collaborate with other team members for quick project turnaround.
Open, customizable, and free to download and modify, Raw lets users create vector-based data visualizations. Data can be safely uploaded from apps to computers, plus it can be exported as an SVG or PNG and embedded in your webpage.
If you're looking for a data viz tool with mapping, InstantAtlas is worth checking out. This tool enables you to create highly-interactive dynamic and profile reports that combine statistics and map data to create engaging data visualizations.
Billed as a "computational knowledge engine", the Google rival WolframAlpha is really good at intelligently displaying charts in response to data queries without the need for any configuration. If you're using publically available data, this offers a simple widget builder to make it really simple to get visualizations on your site.