sys
tool
lib
analyze
format
Mostly Graphics
The following packages were designed for or will install on various
UNIX platforms, although the focus is on those that will work on
Linux platforms.
An interesting tutorial/overview of scientific visualization which features quite a few examples from the geosciences is Signal processing aspects of scientific visualization by Robert J. Moorhead II and Zhifan Zhu, "IEEE Signal Processing Magazine", Sept. 1995. You might want to buy a copy of the magazine seeing how a B&W xerox copy doesn't really do the examples justice.
Here are some links to further information (graphics sites, visualization tutorials, etc.) on the the topic.
Scientific Visualization Sites
This page is an annotated bibliography of scientific visualization web sites around the world.
Tutorial on Visualization - Dr. Gitta Domik
A history and overview of scientific data visualization.
Interactive Visualization of Volumetric Data
Rules and Principles of Scientific Data Visualization - H. Senay and E. Ignatius
Gallery of Data Visualization - Michael Friendly
The graphics packages have been divided into three separate sections according to how they are used, the distinctions between which will be explained in the prefatory note in each section.