EXTEND (CCP4: Unsupported Program)

NAME

extend - Extend Fourier maps

SYNOPSIS

extend mapin foo_in.map mapout foo_out.map [ xyzin foo_in.brk ]
[Key-worded input]

DESCRIPTION

The program EXTEND generates any part of a map from a map calculated by the FFT program which typically contains only one asymmetric unit. This version will now construct an output section from more than one input section if necessary.

KEY WORDED INPUT

The data control lines are identified by keywords. Only the first 4 letters of each keyword are necessary. Some data cards are optional. The available keywords are: XYZLIM, SYMMETRY, BORDER and END. They are all optional, but some must be specified if XYZIN isn't assigned.

DESCRIPTION OF KEYWORDS

XYZLIM <xmin> <xmax> <ymin> <ymax> <zmin> <zmax>

Output map limits in grid points or fractions of cell edge. If this card is not given XYZIN must be assigned. The program then reads the coordinates to determine the map limits.

SYMMETRY <Name> | <Number>

Followed by space group Name (e.g. P212121) or Number (e.g. 19). Symmetry is usually read from the header of the input map so this keyword is not normally needed. Use it only to change symmetry, or if no symmetry is present in the map. This is needed after certain non-CCP4 programs e.g. from Uppsala.

MAPSYM <Name> | <Number>

Inserts the specified space group symmetry operators into the output map, but does not use them for extending the map. This may be needed after `skewing' a map, since that map will have only X,Y,Z symmetry, but be careful.

BORDER <width>

<width> of border in Angstroms to add to coordinate limits.

Default = 10 Angstroms. This card is only needed if XYZLIM is not given; otherwise limits are determined from the XYZIN coordinate file.

END

Ends input.

INPUT AND OUTPUT FILES

MAPIN: input map (from FFT)
MAPOUT: extended output map
XYZIN: input coordinates, optional unless limits not given.

PROGRAM FUNCTION

The program EXTEND is used to extend the range of Fourier map or to calculate a different part of the unit cell from that input. Its main use is in preparing data for map plotting programs such as NPO (PLUTO) or O. The newer program MAPMASK is probably a faster alternative.

AUTHORS

Phil Evans, MRC-LMB, Cambridge

EXAMPLES

The following is an example of control data for extending a map


extend MAPIN 3fo2fc.map MAPOUT 3fo2fc.ext << END-extend
XYZLIM -1.0 0.5  0.1 0.9  -0.3 1.0
END-extend