linecat

linecat (Line Catalog Explorer) is a desktop viewer for spectral line catalogs such as CDMS. It loads a catalog converted to CSV, filters the transitions by frequency range and by the quantum numbers of the upper and lower states, shows the result in a table, exports the selection, and draws an interactive energy-level diagram of the selected transitions (with secondary transitions, hover information and a LaTeX/TikZ export).

Supported species: OH, CH3OH, SiO, NH3. Adding a species means adding its quantum-number rules to linecat/molecules.py.

Installation

Python 3.10 or newer. With pipx (its own environment, recommended):

pipx install linecat

or with pip, in an environment of your choice:

pip install linecat

To start it with a double-click, run once:

linecat install-app

This adds Line Catalog Explorer to your Applications folder (macOS), the Start menu (Windows) or the applications menu (Linux), with its own icon. It starts the linecat of the Python you ran the command with, and keeps working after updates.

To update, use Help → Check for Updates… in the app (it also checks quietly at start-up) or linecat update in a terminal.

For development, install from a clone: git clone https://github.com/vahid-anari/linecat.git, then pip install -e ".[dev]" in the folder; such a copy is updated with git pull.

Use

linecat                       open the viewer
linecat my_catalog.csv        open a catalog at start
linecat convert               convert the shipped CDMS files into the current folder
linecat convert OH --catalogs my_cats --output-dir out   convert your own .cat files
linecat update                update from PyPI (asks first; --check only looks)
linecat install-app           add the app to Applications / Start menu (--remove to undo)
linecat --version

File → Open Built-in Catalog → OH / CH3OH / SiO / NH3 (⌘1–⌘4) opens a catalog that ships with linecat; File → Open Catalog… loads any other CSV; the quantum-number filters and the frequency range narrow the table; File → Export Table as CSV… writes what is shown; Transitions → Show Energy-Level Diagram draws the selected lines (hover for ν and τ, double-click a transition for the lines from its lower level). Right-click a column header for colours, alignment, font and columns.

Catalogs

linecat ships, for OH, CH3OH, SiO and NH3, the CDMS .cat files, the CDMS documentation of each entry (PDF) and a picture of the molecule, one folder per species (src/linecat/data/molecules/<SPECIES>/); the main window shows them in its Molecule box, and Help → CDMS Documentation opens the general CDMS documents. On first start, and after every linecat update, it converts them to read-only CSV files in the application-data folder (macOS: ~/Library/Application Support/linecat/catalogs/; File → Show Built-in Catalogs Folder). If a file goes missing it is rebuilt. Your own .cat files (a newer CDMS release, say) can be converted with File → Convert CDMS Catalogs… or linecat convert --catalogs DIR.

The catalog data come from the Cologne Database for Molecular Spectroscopy (CDMS); please cite Müller et al. 2001, A&A 370, L49; Müller et al. 2005, J. Mol. Struct. 742, 215; and Endres et al. 2016, J. Mol. Spectrosc. 327, 95. The catalog format and the SPCAT program are described by Pickett et al. 1998, J. Quant. Spectrosc. Radiat. Transfer 60, 883. The CDMS documentation pages included with linecat are reproduced with credit to CDMS.

Documentation

Help → User Guide opens the User Guide (PDF): the windows, the energy-level diagram, converting catalogs, the command line, adding a species, and the equations behind the derived columns. What changed in each version is in CHANGELOG.md.

Development

pip install -e ".[dev]"
pytest

The window tests run offscreen with the small catalog in tests/data/. The User Guide sources are in docs/ (user_guide.tex, with the equations in equations.tex); after a change, sh tools/build_docs.sh rebuilds it into src/linecat/data/user_guide.pdf (needs a TeX installation, e.g. MacTeX). The screenshots in docs/figures/ are taken by hand on a Mac (⌘⇧4, Space, ⌥-click for a window without shadow). Pushing a tag vX.Y.Z publishes a GitHub Release with that version's section of CHANGELOG.md.

Citing

If you use linecat in published work, please cite it; GitHub's Cite this repository button gives the reference (from CITATION.cff). Please also cite CDMS for the catalog data (see Catalogs).

License

MIT License. See LICENSE.

Author

Vahid Anari · GitHub · LinkedIn

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