I'd like to introduce one of the more popular tools used for visualizing data within several scientific disciplines: ParaView. ParaView started as a joint project between Kitware, Inc., and Los Alamos National Laboratory back in 2000. The first public release was version 0.6, which came out in 2002. Since then, ParaView has become one of the most popular visualization packages for visualizing large data sets.
Because it's open source, it should be available in most, if not all, package repository systems. For example, in Debian-based distributions, you should be able to install it with the command:
sudo apt-get install paraview
Starting it the first time should give you an empty workspace, ready for you to get to work.
Figure 1. When you first start ParaView, you'll see a new, empty layout to start your visualization.
Two major parts populate the bulk of the window. The right-hand side is the main display pane where the visualization will appear. The left-hand pane shows the list of objects being visualized, along with their properties. At the top, there is a toolbar of the common functions in ParaView.
To play with ParaView, you'll need some data. If you don't have any data of your own to use, you can grab some data provided as part of the ParaView Tutorial. More documentation and sample scripts are also available there.
Let's assume you're going to use the sample data as you learn how to use ParaView. To load the data, click File→Open, and navigate to where you unpacked the sample data.
While you're here, take a quick look at the list of all of the file types ParaView supports. For example, you can load the data stored in the file can.ex2. You won't see anything displayed right away. In the bottom part of the left-hand side pane, you should see the properties for the newly loaded data file. For now, you can just accept the defaults and click the apply button. You then should see the data visualized in the main pane.
Figure 2. The data in the sample file can.ex2 renders as a half cylinder attached to a rectangle on the end.
Clicking and dragging on the image allows you to rotate the view, so you can see the entire object from various angles.