Skymap¶

Skymap Diagram

OTSO.skymap ¶

skymap(
    Stations: Union[str, Sequence[str]],
    customlocations: Optional[list] = None,
    solar_wind_params: SolarWindParams = {},
    geomagnetic_params: GeomagneticParams = {},
    tsyganenko_params: TsyganenkoParams = {},
    datetime_params: DateTimeParams = {},
    magfield_params: MagFieldParams = {},
    integration_params: IntegrationParams = {},
    particle_params: ParticleParams = {},
    rigidity_params: RigidityParams = {},
    coordinate_params: CoordinateParams = {},
    computation_params: ComputationParams = {},
    data_retrieval_params: DataRetrievalParams = {},
    custom_field_params: CustomFieldParams = {},
    skymap_params: SkymapParams = {},
) -> list

Compute geomagnetic cutoff rigidities over a range of zenith and azimuth combinations for given neutron monitor stations, or user-defined locations. Useful for showing the East-West asymmetry of cosmic-ray arrival.

Upon calling this function, OTSO will perform particle tracing simulations based on the specified parameters, returning the cutoff rigidities as functions of zenith and azimuth, and related metadata.

Parameters:

Stations (str | list) –

Station name(s) or identifiers used for cutoff calculations.
customlocations (list, default: None ) –

Custom locations as [["NAME", lat, lon]].
cutoff_comp (str) –

Cutoff computation method ("Vertical", "Apparent", "Custom").
datetime_params (DateTimeParams, default: {} ) –
Date/time parameters.

Available keys:
- year (int, default=2024): Year (e.g., 2023)
- month (int, default=1): Month (1–12)
- day (int, default=1): Day (1–31)
- hour (int, default=12): Hour (0–23)
- minute (int, default=0): Minute (0–59)
- second (int, default=0): Second (0–59)
magfield_params (MagFieldParams, default: {} ) –
Magnetic field models.

Available keys:
- internalmag (str, default="IGRF"): "NONE", "IGRF", "Dipole", "Custom Gauss", "CHAOS"
- externalmag (str, default="TSY89c"): "NONE", "TSY87short", "TSY87long", "TSY89a", "TSY96", "TSY01", "TSY01S", "TSY04", "TSY89c", "TSY15N", "TSY15B", "TA16_RBF", "TSY89_refit", "MHD"
- boberg (bool, default=False): Enable Boberg extension
- bobergtype (str, default="EXTENSION"): "EXTENSION", "CONTINUOUS", "DST_DEPENDENT", "DST_MIDPOINT"
- magnetopause (str, default="Kobel"): "NONE", "Kobel", "Sibeck", "Lin", "Sphere", "aFormisano"
- spheresize (float, default=25): Spherical boundary radius (Re)
- AdaptiveExternalModel (bool, default=False): Auto-select external model
- optimise_tsy (bool, default=False): Use the faster implementation of the selected Tsyganenko model (affects externalmag="TSY01", "TSY01S", "TSY04", or "TSY96"; other models are unaffected by this flag). Both settings give numerically identical results (all known bugs are fixed in both); True is just faster
rigidity_params (RigidityParams, default: {} ) –
Rigidity scanning.

Available keys:
- startrigidity (float, default=20): Initial rigidity (GV)
- endrigidity (float, default=0): Final rigidity (GV)
- rigiditystep (float, default=0.01): Step size (GV)
- rigidityscan (str, default="ADAPTIVE"): Penumbra scanning ("ADAPTIVE"/"ON"/"OFF"). "ADAPTIVE" extends the fine scan until the penumbra is bounded by clean guard bands; "ON" uses a fixed ±0.75 GV window around a 0.25 GV coarse scan; "OFF" scans the full range
skymap_params (SkymapParams, default: {} ) –
Sky map zenith and azimuth resolution parameters

Available keys:
- zenithstep (float, default=15): Zenith resolution
- azimuthstep (float, default=45): Azimuth resolution
- maxzenith (float, default=75): Maximum deviation from the zenith
- minzenith (float, default=0): Minimum deviation from the zenith
- maxazimuth (float, default=360): Maximum azimuth value
- minazimuth (float, default=0): Minimum azimuth value
solar_wind_params (SolarWindParams, default: {} ) –
Solar wind parameters. Defaults are quiet-time medians (Kp <= 1) of OMNI data, 1996-2025.

Available keys:
- vx (float, default=-359.4): Solar wind velocity x-component (km/s)
- vy (float, default=0): Solar wind velocity y-component (km/s)
- vz (float, default=0): Solar wind velocity z-component (km/s)
- bx (float, default=0.11): IMF x-component (nT)
- by (float, default=-0.16): IMF y-component (nT)
- bz (float, default=0.58): IMF z-component (nT)
- by_avg (float, default=-0.17): Averaged IMF By over last 30mins (nT)
- bz_avg (float, default=0.59): Averaged IMF Bz over last 30mins (nT)
- density (float, default=4.94): Solar wind density (particles/cm³)
- pdyn (float, default=1.31): Solar wind dynamic pressure (nPa); computed from density and velocity when 0, or when density or velocity is given without pdyn
geomagnetic_params (GeomagneticParams, default: {} ) –
Geomagnetic indices. Defaults are quiet-time medians (Kp <= 1) of OMNI data, 1996-2025.

Available keys:
- Dst (float, default=-4): Dst index (nT)
- kp (float, default=0.7): Kp index (0-9)
- n_index (float, default=0.145): Newell coupling function
- b_index (float, default=0.032): Boynton coupling function
- sym_h_corrected (float, default=-18.07): Corrected SYM-H index (nT)
tsyganenko_params (TsyganenkoParams, default: {} ) –
Tsyganenko model coefficients. Defaults are quiet-time medians (Kp <= 1) of OMNI data, 1996-2025.

Available keys:
- G1 (float, default=0.38): Tsyganenko G1 coefficient
- G2 (float, default=0.12): Tsyganenko G2 coefficient
- G3 (float, default=0.47): Tsyganenko G3 coefficient
- W1 (float, default=0.07): Tsyganenko W1 coefficient
- W2 (float, default=0.06): Tsyganenko W2 coefficient
- W3 (float, default=0.13): Tsyganenko W3 coefficient
- W4 (float, default=0.03): Tsyganenko W4 coefficient
- W5 (float, default=0.05): Tsyganenko W5 coefficient
- W6 (float, default=0.08): Tsyganenko W6 coefficient
integration_params (IntegrationParams, default: {} ) –
Integration settings.

Available keys:
- intmodel (str, default="Boris-Buneman"): "4RK", "5RK", "6RK", "Vay", "HC", "Boris-Buneman"
- gyropercent (float, default=1): Step size as a percentage of the gyration period. With adaptivestep=True (default) it caps each step using the local field; with adaptivestep=False the step is fixed for the whole trace at this percentage of the gyration period at the launch point
- minaltitude (float, default=20): Minimum altitude (GDZ = km or other = Re)
- maxdistance (float, default=100): Maximum path length travelled (Re), not distance from Earth; 0 disables this check (use 0 for long trapped-particle runs: a 0.6c proton travels 100 Re in ~4 s)
- maxtime (float, default=0): Maximum flight time in seconds (lab frame); 0 = no limit
- mintrapdist (float, default=0): Minimum trapping distance
- startaltitude (float, default=20): Starting altitude (GDZ = km or other = Re)
- betaerror (float, default=0.001): Maximum allowed beta error for integration steps %
- totalbetacheck (bool, default=False): Enable cumulative beta check during integration
- adaptivestep (bool, default=True): Enable adaptive time steps
- maxsteps (int, default=0): Maximum number of integration steps; 0 = no limit
particle_params (ParticleParams, default: {} ) –
Particle settings.

Available keys:
- Anum (int, default=1): Atomic number (-1=muon, 0=electron, 1=proton, 2=alpha)
- anti (str, default="YES"): YES = anti-particle, NO = particle
coordinate_params (CoordinateParams, default: {} ) –
Coordinate systems.

Available keys:
- inputcoord (str, default="GDZ"): Input coordinate system; "GDZ", "GEO", "GSM", "GSE", "SM", "GEI", "MAG", "SPH", "RLL"
computation_params (ComputationParams, default: {} ) –
Computation settings.

Available keys:
- corenum (int, default=None): Number of CPU cores for multicore processing
- threadnum (int, default=None): Number of threads per CPU core for Fortran computations
- Verbose (bool, default=True): Enable verbose output
data_retrieval_params (DataRetrievalParams, default: {} ) –
Data retrieval.

Available keys:
- serverdata (str, default="OFF"): Server data retrieval from OMNI
- livedata (str, default="OFF"): real-time data retrieval from NOAA
custom_field_params (CustomFieldParams, default: {} ) –
Custom fields.

Available keys:
- g (list, default=None): Gauss g coefficients
- h (list, default=None): Gauss h coefficients
- max_degree (int, default=13): Max degree of spherical harmonic expansion
- MHDfile (str, default=None): MHD simulation file
- MHDcoordsys (str, default=None): MHD coordinate system
- MHDgridtype (str, default="auto"): How the MHD grid is looked up - "auto" detects per-axis spacing automatically, "uniform" forces the fast fixed-spacing path (only correct if every axis really is evenly spaced), "stretched" forces the general path needed for a grid whose resolution varies with position (e.g. finer near Earth)
- MHDinterpolation (str, default="trilinear"): How the field is reconstructed between grid points - "trilinear" is the classic fast corner-blend (kinked gradients at cell boundaries), "tricubic" is a smooth C^1 fit that's far more accurate in smooth field regions but can overshoot near sharp gradients/boundaries, "monotonic" is the same tricubic fit with overshoot limiting (recommended for general use), "divfree" returns the curl of an interpolated vector potential so the field is exactly divergence-free (for long quasi-trapped trajectories; less point-wise accurate than "tricubic"; the gridded field must itself be divergence-free, e.g. an external-only field - a warning is issued otherwise)

Returns:

list ( list ) –
[skymap_dataframe, readme_text]
- skymap_dataframe: Cutoff data values per input station and zenith and azimuth combination in a pandas dataframe. (Ru, Rc, Rl, PTF)
- readme_text: OTSO computation summary

Examples:

    import OTSO

    if __name__ == "__main__":

        stations = ["ROME"] # list of neutron monitor stations (using their abbreviations)

        # Using parameter groups
        skymap_results = skymap(
            Stations=stations,
            computation_params={"corenum": 1,"threadnum": 8},
            datetime_params={"year": 2005,"month": 5,"day": 1,"hour": 0},
            integration_params={"gyropercent": 10},
            magfield_params={"internalmag": "IGRF","externalmag": "NONE"},
            rigidity_params={"rigiditystep": 0.01},
            skymap_params={"zenithstep": 5,"azimuthstep": 15}
        )

        # Access the results
        skymap_data, metadata = result