CMPR is a Graphical Manual Powder Indexing and Powder Diffraction Toolkit written in
Tcl/Tk by Brian Toby which links a variety of tools together. One of the very nifty features
is the graphical display of HKL lines over raw data, then (using scroll bars of the
cell axis and angle values) and moving the overlaid HKL line positions in near real time.
This is useful when you have a cell from Electron Microscopy or similar analysis, or where you
know some of the cell values but need to experiment with the data to get a cell and spacegroup
in ways that auto-indexing programs do not allow.
This is also useful for teaching purposes and it can easily be shown why determining the
cell and spacegroup from powder data can be so non-trivial. It also allows intuitive
graphical manual indexing.
An Overview of the program is described at
http://www.ncnr.nist.gov/programs/crystallography/software/cmpr/