Utility Functions

Utility functions for the satkit package

API Reference

Utility functions for SatKit

satkit.utils.build_date()

Return build date of this satkit library as a string

Returns:

  • str

    Build date of this satkit library

satkit.utils.datadir()

Return directory currently used to hold necessary data files for the directory

Data directory is 1st of following directories search that contains the data files listed in “update_datafiles”

  • MacOS:

    1. Directory pointed to by SATKIT_DATA environment variable

    2. $DYLIB/satkit-data where $DYLIB is location of compiled python satkit library

    3. $HOME/LIBRARY/Application Support/satkit-data

    4. $HOME/.astro-data

    5. $HOME

    6. /usr/share/astro-data

    7. /Library/Application Support/astro-data

  • Linux:

    1. Directory pointed to by SATKIT_DATA environment variable

    2. $DYLIB/satkit-data where $DYLIB is location of compiled python satkit library

    3. $HOME/.astro-data

    4. $HOME

    5. /usr/share/astro-data

  • Windows:

    1. Directory pointed to by SATKIT_DATA environment variable

    2. $DYLIB/satkit-data where $DYLIB is location of compiled python satkit library

    3. $HOME/.astro-data

    4. $HOME

satkit.utils.datafiles_exist()

Check if data files are found

Returns:

True if data files are found

False if data files are not found

Return type:

bool

satkit.utils.dylib_path()

Location of the compiled library

Returns:

Path to the compiled library

Return type:

str

satkit.utils.githash()

Return git hash of this satkit build

Returns:

  • str

    Git hash of this satkit build

satkit.utils.set_datadir(datadir)

Set the data directory

Parameters:

datadir (str) – Path to the data directory

Returns:

None

Raises:

RuntimeError – If the directory does not exist

satkit.utils.update_datafiles(**kwds)

Download & store data files needed for “satkit” computations

Keyword Arguments:

  • overwrite (bool) – Download and overwrite files if they already exist

  • dir (string) – Target directory for files. Uses existing data directory if not specified. (see “datadir” function)

Notes

  • Files include:

    • EGM96.gfc : EGM-96 Gravity Model Coefficients

    • JGM3.gfc : JGM-3 Gravity Model Coefficients

    • JGM2.gfc : JGM-2 Gravity Model Coefficients

    • ITU_GRACE16.gfc : ITU Grace 16 Gravity

    • tab5.2a.txt : Coefficients for GCRS to GCRF conversion

    • tab5.2b.txt : Coefficients for GCRS to GCRF conversion

    • tab5.2d.txt : Coefficients for GCRS to GCRF conversion

    • SW-ALL.csv : Space weather data, updated daily

    • leap-seconds.txt : Leap seconds (UTC vs TAI)

    • EOP-All.csv : Earth orientation parameters, updated daily

    • linux_p1550p2650.440 : JPL Ephemeris version 440 (~ 100 MB)

  • The space weather and earth orientation parameters files are updated

    daily and will always be downloaded regardless of the overwrite flag

satkit.utils.version()

Return version of this satkit library as a string

Returns:

  • str

    Version of this satkit library