Metadata keys

The standard metadata keys set when data are loaded and processed. See Metadata for how metadata are organised.

Accessing metadata

Lookup	Returns
`spec[:ns]`	spectrum metadata (a key from Spectra)
`spec[F1Dim, :swppm]`, `spec[1, :swppm]`	axis metadata (a key from Frequency and time dimensions), by dimension type or number
`acqus(spec, :te)`	an acquisition parameter from the `acqus` file
`acqus(spec, :p, 1)`	an arrayed acquisition parameter (here `P1`), indexed as in TopSpin
`acqus(spec, :vdlist)`	an auxiliary file (see Auxiliary files)
`metadata(spec)`, `metadata(spec, F1Dim)`	the whole dictionary for the spectrum, or for one axis

using NMRTools
spec = exampledata("2D_HN")
spec[:ns], spec[F1Dim, :swppm], acqus(spec, :p, 1)

(2, 18.031507535006423, 9.199999999999998e-6)

Times are in seconds and frequencies in Hz (see Time and frequency units).

Key	Description
`:acqusfilename`	path to acqus file
`:acqus`	contents of acqus file, as a dictionary
`:acqu2s`, `:acqu3s`	contents of acqu2s/acqu3s files (if present)
`:date`	experiment timestamp (completion time)
`:experimentfolder`	path to experiment
`:field`	field strength, in T
`:filename`	spectrum filename or template
`:format`	input file format (`:nmrpipe`, `:pdata`, …)
`:label`	short label (first line of title pdata file), used for captions
`:ndim`	number of dimensions
`:noise`	RMS noise level (see `estimatenoise`)
`:nuclei`	set of `Nucleus` values
`:ns`	number of scans
`:pulseprogram`	pulse programme (PULPROG)
`:rg`	receiver gain
`:solvent`	solvent string, e.g. `"H2O+D2O"`
`:temperature`	temperature, in K
`:title`	spectrum title (contents of title pdata file)
`:topspin`	TopSpin version used for acquisition

Keys marked † are set on time dimensions by loadfid and carried over to the frequency dimension by ft.

Key	Description
`:aq`	acquisition time, in seconds
`:bf`	base frequency, in Hz
`:firstpoint` †	scaling factor applied to the t = 0 point
`:grpdly` †	digital filter group delay, in dwell times (direct dimension; 0 after `ft`)
`:label`	short label
`:mcindex`	imaginary unit of the dimension (`1` for `im1`, …), `nothing` if none
`:npoints`	final number of real data points in dimension (after extraction)
`:nucleus`	`Nucleus` of the dimension
`:offsethz`	carrier offset from bf, in Hz
`:offsetppm`	carrier offset from bf, in ppm
`:phase`	total phase correction applied, `(p0=…, p1=…)` in degrees, p0 at the first point
`:pseudodim`	flag indicating non-frequency domain data (`false` for frequency domain)
`:quadrature` †	quadrature scheme of an indirect dimension, e.g. `:states_tppi`
`:referenceoffset`	applied referencing, in ppm
`:region`	extracted region, expressed as a range in points, otherwise `missing`
`:sf`	carrier frequency, in Hz
`:swhz`	spectrum width, in Hz
`:swppm`	spectrum width, in ppm
`:td`	number of complex points acquired, including LP
`:tdzf`	number of complex points when FT executed, including LP and ZF
`:window`	`WindowFunction` encoding applied apodization

Auxiliary files in the experiment folder are read when data are loaded and returned by acqus, with their values converted to NMRTools units:

Key	Contents
`:vclist`	variable loop counters (dimensionless)
`:vdlist`	variable delays, in seconds
`:valist`	variable amplitudes, in dB (converted from W if necessary)
`:vplist`	variable pulse lengths, in seconds
`:fq1list` … `:fq8list`	frequency lists, as `FQList` (see Frequency lists)

acqus returns nothing for a list that is not present.