how do you need to plot them / what are the requirements.
I should do some more speed testing, but e.g. it's possible to get SVG to draw "markers" at every point in a single polygon, and fairly quickly in some renderers.
I'd also expect SVG to be faster if you have a reasonable amount of shapes but only move one or two. In canvas you have to redraw everything yourself, with SVG you simply change the coordinates of the shapes you want to move, and the browser takes care of redrawing what is needed.
It's based on pure Canvas so there are no other requirements. I am still working on the documents but the source code is commented well. Right now it creates scatter plots but I may add other types of plots later. If you intend to help it in your application, I will be happy to work with you.
You could draw SVG markers at every point but with the DOM and everything, it just becomes very slow. protovis (a great SVG based library) mention the number 10,000 points at which SVG starts becoming unusable. I am able to plot 25k+ points.
I should do some more speed testing, but e.g. it's possible to get SVG to draw "markers" at every point in a single polygon, and fairly quickly in some renderers.