I need to plot discrete X,Y data as a MAP in a PNG or GIF file colour-coded to indicate discrete values.
All the Javascript Chart libraries I've seen do pie charts, line graphs, bar charts, etc, but NOT scatterplots.
Does anyone know the name of a library capable of scatterplots?
My current solution is to render the map as an HTML table (and screen-capture) where the cells are empty but have coloured backgrounds, depending on the discrete value. As you would expect, this is slow. Particularly when X and Y can take values 0 to 200, or more.
It also suffers from distortion when browsers choose cell size. Browsers decrease cell width across the page as they realise their original choice was too great. Circular maps end up looking egg-shaped and one end is more pointy than the other