NeXus Attributes


Global Attributes

NameTypeDescription
file_nameNX_CHARFile name of original NeXus file to assist in identification if the external name has been changed
file_timeISO 8601Date and time of file creation
NeXus_versionNX_CHARVersion of NeXus API used in writing the file
userNX_CHARName of user responsible for producing the file
affiliationNX_CHARUser's affiliation
addressNX_CHARUser's postal address (complete)
telephone_numberNX_CHARUser's telephone number
fax_numberNX_CHARUser's fax number
emailNX_CHARUser's e-mail address

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Data Attributes

NameTypeDescription
unitsNX_CHARUnits of data which must conform to the standard defined by the Unidata UDunits utility (in particular, see udunits.dat)
signalNX_INT32Defines which data set contains the signal to be plotted - set to 1 for main signal
axisNX_INT32Defines the rank of the signal data for which this data set is a dimension scale in order of the fastest varying index i.e. if the array being stored is data, with elements data[j][i] in C and data(i,j) in Fortran, "axis" would have the following values :
  • ith dimension: axis = 1
  • jth dimension: axis = 2
  • etc.
primaryNX_INT32Defines the order of preference for dimension scales which apply to the same rank of signal data - set to 1 for preferred dimension scale
long_nameNX_CHARDefines title of signal data or axis label of dimension scale
calibration_statusNX_CHARDefines status of data value - set to "Nominal" or "Measured"
histogram_offsetNX_FLOAT32Defines the offset from the first data point to its bin boundary.
i.e. left_bin = data[1] - histogram_offset
- set to 0 if the data are not histograms. The points themselves should be set to the bin centers. For reasoning behind this design, see note on histograms.
checksumNX_INT32Sum of data array acting as a check on data integrity
versionNX_CHARVersion of XML DTD file or schema on which the NeXus file is based. Should only be used with the "analysis" data item in an NXentry group.
URLNX_CHARThe URL of the XML DTD file or schema on which the NeXus file is based. Should only be used with the "analysis" data item in an NXentry group.

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Comments to: Ray Osborn <ROsborn@anl.gov>
Revised: Wednesday, September 29, 1999

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