Tioga is a Ruby library for scientific plotting which uses pdfTeX as a renderer. This allows production of publication quality vector format graphics. Almost any (La)TeX text/formulas may appear in the image and are rendered properly.
Example of Tioga visualization:
Tioga is limited to 2D visualization. It is particulary useful for traditional function plots, 2D fields in false color, and contour plotting.
Tioga is Free Software.