[Animl-develop] Examples of JCAMP-DX files with integer values

[Peter J. L. <pet...@ni...>]

Anh Dao,

   Please find attached two JCAMP-DX files which contain
integer values for absorbance and transmittance values:

epa-ir.dx    This file contains a gas phase spectrum for
             butanoic acid. It is part of the EPA's gas
             phase IR collection (which was later
             transferred to NIST).

quant-ir.dx  This file contains a gas phase spectrum for
             methyl ethyl ketone. It comes from the NIST
             Quantitative Infrared Database (SRD 79) which
             is developed by the NIST Analytical Chemistry
             Division.

   The data in both of these files could be represented
in AnIML by simply multiplying the integer Y values by
the JCAMP-DX parameter "YFACTOR" and storing the resulting
values as floating point numbers. Doing this may result
in a loss of information about reported digits and any
rounding due to the integer representation. Since compression
in JCAMP-DX requires data in integer form, compressed
JCAMP-DX data will consist of integers multiplied by a
floating point value.

   In the case of the first file such a conversion will
hide the fact that some values are only reported to two
or three digits. In the second file the fact that the
multiplier is reported with five digits (versus up to
eight for the integer values) will be lost.

   I hope these examples are of use to you.

Peter

================================================
Peter J. Linstrom
NIST, Physical and Chemical Properties Division
Phone: (301) 975-5422
================================================