Protovis
Protovis composes custom views of data with simple marks such as bars and dots. Unlike low-level graphics libraries that quickly become tedious for visualization, Protovis defines marks through dynamic properties that encode data, allowing inheritance, scales and layouts to simplify construction.
Protovis is free and open-source, provided under the BSD License. It uses JavaScript and SVG for web-native visualizations; no plugin required (though you will need a modern web browser)! Although programming experience is helpful, Protovis is mostly declarative and designed to be learned by example.
Protovis is no longer being developed. The developers have moved on to a new visualization library, D3.
The SSH Open Marketplace is maintained and will be further developed by three European Research Infrastructures - DARIAH, CLARIN and CESSDA - and their national partners. It was developed as part of the "Social Sciences and Humanities Open Cloud" SSHOC project, European Union's Horizon 2020 project call H2020-INFRAEOSC-04-2018, grant agreement #823782.
