Fixed-Width Text (.fwf / .prn)
.prn.fwfLegacy mainframes, Fortran simulations, NOAA/astronomy datasets, and print-formatted text exports
What it is
Plain text format where data columns are aligned by fixed character column widths rather than delimiters. Read via an offline Python/pandas engine.
Who produces it
Fortran scientific simulation codes, meteorological observations, financial mainframe systems, and older lab software.
What we read / what we don't read
What we read
- Fixed-width numeric and text columns with automatically inferred column widths
- Explicit user-configurable column width lists (widths) when inference needs customization
What we don't read
- Ragged text files without consistent vertical character column alignment
- Multi-section files where width definitions change between data blocks
How to import it into AltaiPlot
- Open AltaiPlot and drag your .fwf or .prn file onto the window, or use File → Import.
- AltaiPlot analyzes character column boundaries and splits lines into columns.
- Preview the inferred table structure.
- Click Import.
Auditability note: this page's capability claims are sourced fromresources/python/app_sidecar.py:1584 — see the full format list for every extension AltaiPlot recognizes.