CCP4 -> XPLOR map

Eric Pettersen pett at
Wed Jan 10 16:59:06 EST 1996

mb1daw at (D Waller) wrote:
> Can anyone suggest a quick way to go from a CCP4 format map
> to an XPLOR format map which we can then read into MidasPlus?
> Alternatively can someone give me a format description of the
> XPLOR map and we could then write a conversion jiffy.

	Unfortunately I am unfamiliar with the CCP4 format and am unaware
of any conversion utilities from CCP4 to X-PLOR.  If you wish to write a
conversion tool yourself, the X-PLOR manual documents the density file
format with the FORTRAN code used to write the file.  The X-PLOR manual
is available online and the specific URL for the format of the electron
density file is:

the manual is mirrored in England as well, so a closer URL might be:

	The least well-explained part of the FORTRAN code is what populates
the density matrix itself, which is probably because the contents vary
based on what options were used when the map was computed.  If the default
flags are used then (to the best of my knowledge) the density map is scaled
so that the average density of the unit cell is at 0.0 and a 1 sigma
standard density deviation is at 1.0.

	I'm willing to assist your conversion attempt as best I can if you
have any further questions, etc.
			Eric Pettersen
			UCSF Computer Graphics Lab
			pett at (NeXTmail capable)

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