CCP4 Roadmaps
	DATA REDUCTION

DATA PROCESSING AND REDUCTION

The plain rectangular boxes represent tasks as in the CCP4 Graphical User Interface, the steps to take for data reduction. The stippled rectangular boxes represent external programs. 'Convert to MTZ & Standardise' is not part of the Data Reduction module in the Interface; it is part of the Reflection Data Utilities module.

The ellipsoids represent the input and output to and from the various tasks. Some data processing is required before CCP4 programs can be used, hence the stippling of the 'X-ray diffraction data' ellipsoid.

Auxiliary CCP4 programs used in these tasks

CAD

Collect and sort crystallographic reflection data from several files

CROSSEC

Interpolate X-ray cross sections and compute anomalous scattering factors

F2MTZ

Convert at formatted reflection file to MTZ format

FREERFLAG

Tag each reflection in an MTZ file with a flag for cross-validation

REBATCH

Alters batch numbers in unmerged MTZ file

REINDEX

Reindex or change symmetry of unmerged or merged MTZ file (can also be done with COMBAT/SORTMTZ/SCALEPACK etc.)

ROTAPREP

Produce an MTZ file in multirecord form suitable for input to SCALA (superseded by COMBAT)

TRACER

Lattice TRAnsformation and CEll Reduction to analyse for other possible unit cells

WILSON

Wilson plot to determine scale factor / temperature factor (also incorporated into TRUNCATE)

MADNES data

ABSURD

Initial processing of intensity files from MADNES (can be used for DENZO data, too)

UNDUPL

Remove duplicates from MADNES data, after ABSURD

Other non-CCP4 programs

Crystal Twinning Server

Merohedral Crystal Twinning Server - forms interface to twinning test

Further reading

CCP4i Documentation on Data Processing

Reindexing

Twinning

FreerUnique

Introduction to Hemihedral Twinning

CCP4 Program Documentation