SPCfile - An SPC file reader in Python

A modern reader for GRAMS/Thermo-Galactic SPC files - a widely used file format in spectroscopy.

Installation

Requires Python >= 3.9 and NumPy. Install directly from this repository using pip:

pip install git+https://github.com/kogens/spcfile.git

Features

SPCfile focuses on a small, practical API for loading SPC files into NumPy arrays. It aims to make common spectroscopy workflows easy (load → inspect metadata → work with x/y arrays), while keeping the implementation straightforward and well-tested.

Supported SPC formats

Currently supported:

• New-format SPC (512-byte header): 0x4B (little-endian, tested) and 0x4C (big-endian, supported but not currently tested due to lack of sample files)
• X modes: implicit evenly-spaced X, explicit global X (TXVALS), and per-subfile X/Y (TXYXYS / "XYXY")
• Multifile (TMULTI) and minimal 4D metadata: .z / .w expose per-subfile coordinates and .w_planes exposes the plane count
• Log text block is read when present

Usage examples

from spcfile import SPCFile

# Load multifile with a shared X axis
spc = SPCFile("multifile.spc")
print(spc)

SPC File: multifile.spc
Date: 2021-03-15 09:21:00
Subfiles: 1
Points per subfile: 1776
Experiment type: General
Units: X='Wavenumber (cm^-1)', Y='Transmittance', Z='Arbitrary', W='Arbitrary'

Datapoints and coordinates are easily accessible as attributes of the SPCFile object:

# Access X, Y, Z values (represented as numpy arrays)
x = spc.x
y = spc.y
z = spc.z

# Subfiles can be indexed like a list
subfile0 = spc[0]
y0 = subfile0.y

Limitations

SPCfile currently rejects old-format 0x4D SPC files.