The most common types of scientific visualizations have, thus far, been two-dimensional plots, either simple cartesian plots or contour plots.  Most analysis tools today give the option of plotting data in three dimensions.  These tools typically rely on perspective plots - that is, they can create the appearance of, say, a topographic surface as it would appear without stereo vision by utilizing the 'trick' of perspective.  The figures on the left show bathymetric data (of a submarine canyon) from off the Washington coast as a standard (100m) contour plot and as a perspective plot of a three-dimensional surface.  Not only does the perspective plot give the observer a more recognizable object, but the 'spikes' in the bathymetry data are immediately observable - no usable choice of contours in the contour plot could tell the user that these spikes exist, or whether there is any pattern to them.  Perspective plots are definitely useful, but the next step in the evolution of scientific visualization is to add motion parallax: the ability to 'rotate' and interact with an object.  We chose VRML as a visualization tool for it's versitality, and because it's an Internet standard.