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VIPIR FTI Interval Plot Example

This example demonstrates how to turn a directory of VIPIR NGI ionogram files into an O-mode frequency–time interval (FTI) plot suitable for documentation. The workflow lives in examples/vipir/fti.py and is intended to be customised with your own campaign archive or station of interest.

Prerequisites

  • A collection of VIPIR NGI files organised by day, e.g. <root>/<year>/<doy>/ionogram/*.ngi[.bz2].
  • pynasonde dependencies installed (see docs/user/install.md).
  • Optional: set VIPIR_SPEED_DEMON_ROOT to the base directory of your archive to avoid editing the script.

Running the example

export VIPIR_SPEED_DEMON_ROOT=/path/to/your/station/individual
python examples/vipir/fti.py

The script will copy a day's worth of ionograms into /tmp/vipir_fti/, generate a flattened RTI dataframe with generate_fti_profiles, and create a figure inside docs/examples/figures/. Inspect fig_file_name and flim arguments in the call to tune the output path and frequency window.

Using the helper directly

from examples.vipir.fti import generate_fti_profiles

rti = generate_fti_profiles(
    folder="/path/to/ngi/files",
    fig_file_name="docs/examples/figures/my_fti.png",
    fig_title="My Campaign / 2024-03-21",
    stn="WI937",
    flim=(3.5, 4.5),
)

rti is a long-form dataframe containing time, range, and the mode-specific power/noise columns, so you can perform additional filtering or statistics before or after plotting.

Output Figure

VIPIR FTI Interval Plot

Figure: O-mode frequency–time interval (FTI) plot for WI937 during the Speed Demon 2022 campaign (DOY 234). Each row shows a frequency band; color represents O-mode power.
  • examples/vipir/fti.py
  • pynasonde/vipir/ngi/source.py — DataSource
  • pynasonde/vipir/ngi/plotlib.py — Ionogram

See Also