Gwyddion is a modular SPM (Scanning Probe Microsopy) data visualization and
analysis tool written with Gtk+.

It can be used for all most frequently used data processing operations
including: leveling, false color plotting, shading, filtering, denoising, data
editing, integral transforms, grain analysis, profile extraction, fractal
analysis, and many more.  The program is primarily focused on SPM data analysis
(e.g. data obtained from AFM, STM, NSOM, and similar microscopes).  However, it
can also be used for analysis of SEM (Scanning Electron Microscopy) data or any
other 2D data.

WWW: http://gwyddion.net/