webgeocalc 1.2.0

Python package for NAIF WebGeoCalc API

In december 2018, JPL/NAIF announced an experimental API RESTful interface for their new WebGeoCalc server (which make online SPICE calculations). Documentation and JavaScript examples are already available.

This package provides a Python interface to make SPICE calculations through this API.

Note the user

WebGeoCalc is not design to handle heavy calculation. If you need to make intensive queries, use Spiceypy or SpiceMiner package with locally hosted kernels.

Install

With pip:

$ pip install webgeocalc

With conda:

$ conda install -c seignovert webgeocalc

Usage

>>> from webgeocalc import API

>>> API.url
'https://wgc2.jpl.nasa.gov:8443/webgeocalc/api'

>>> API.kernel_sets() # /kernel-sets
[<KernelSetDetails> Solar System Kernels (id: 1),
 ...
 <KernelSetDetails> Cassini Huygens (id: 5),
 ...
 <KernelSetDetails> SPICE Class -- Binary PCK Lesson Kernels (Earth) (id: 39)]

>>> API.bodies(5) # /kernel-sets/{kernelSetId}/bodies
[<BodyData> CASSINI (id: -82),
 ...
 <BodyData> SOLAR SYSTEM BARYCENTER (id: 0)]

>>> API.frames('Cassini Huygens') # /kernel-sets/{kernelSetId}/frames
[<FrameData> CASSINI_SATURN_SKR4N_LOCK (id: -82982),
 ...
 <FrameData> ITRF93 (id: 13000)]

>>> API.instruments('Cassini Huygens') # /kernel-set/{kernelSetId}/instruments
[<InstrumentData> CASSINI_CIRS_RAD (id: -82898),
 ...
 <InstrumentData> CASSINI_SRU-A (id: -82001)]

Prepare calculation payload:

>>> from webgeocalc import Calculation

>>> calc = Calculation(
    kernels = 'Cassini Huygens',
    times = '2012-10-19T08:24:00.000',
    calculation_type = 'STATE_VECTOR',
    target = 'CASSINI',
    observer = 'SATURN',
    reference_frame = 'IAU_SATURN',
    aberration_correction = 'NONE',
    state_representation = 'PLANETOGRAPHIC',
)

>>> calc.payload
{'kernels': [{'type': 'KERNEL_SET', 'id': 5}],
 'times': ['2012-10-19T08:24:00.000'],
 'calculationType': 'STATE_VECTOR',
 'target': 'CASSINI',
 'observer': 'SATURN',
 'referenceFrame': 'IAU_SATURN',
 'aberrationCorrection': 'NONE',
 'stateRepresentation': 'PLANETOGRAPHIC',
 'timeSystem': 'UTC',
 'timeFormat': 'CALENDAR'}

Run calculation:

>>> calc.run()
[Calculation submitted] Status: LOADING_KERNELS (id: 19fd1c05-3bfe-47c7-bd16-28612249ae89)
[Calculation update] Status: COMPLETE (id: 19fd1c05-3bfe-47c7-bd16-28612249ae89)
{'DATE': '2012-10-19 08:24:00.000000 UTC',
 'LONGITUDE': 46.18900522,
 'LATITUDE': 21.26337134,
 'ALTITUDE': 694259.8921163,
 'D_LONGITUDE_DT': 0.00888655,
 'D_LATITUDE_DT': -0.00031533,
 'D_ALTITUDE_DT': 4.77080305,
 'SPEED': 109.34997994,
 'TIME_AT_TARGET': '2012-10-19 08:24:00.000000 UTC',
 'LIGHT_TIME': 2.51438831}

>>> from webgeocalc import AngularSeparation

More details can be found in the docs and in the Jupyter Notebooks.

Command Line Interface (cli)

The webgeocalc API can be call directly from the command line interface:

$ wgc-kernels --all
 - Solar System Kernels: (id: 1)
...
 - Cassini Huygens: (id: 5)
...
 - SPICE Class -- Binary PCK Lesson Kernels (Earth): (id: 39)

$ wgc-instruments 'Cassini Huygens' --name ISS
 - CASSINI_ISS_WAC_RAD: (id: -82369)
 - CASSINI_ISS_NAC_RAD: (id: -82368)
 - CASSINI_ISS_WAC: (id: -82361)
 - CASSINI_ISS_NAC: (id: -82360)

$ wgc-state-vector --kernels 5 \
                   --times 2012-10-19T09:00:00 \
                   --target CASSINI \
                   --observer SATURN \
                   --reference_frame IAU_SATURN
API status:
[Calculation submit] Status: COMPLETE (id: 041bf912-178f-4450-b787-12a49c8a3101)

Results:
DATE:
> 2012-10-19 09:00:00.000000 UTC
DISTANCE:
> 764142.63776247
SPEED:
> 111.54765899
X:
> 298292.85744169
Y:
> -651606.58468976
Z:
> 265224.81187627
D_X_DT:
> -98.8032491
D_Y_DT:
> -51.73211296
D_Z_DT:
> -2.1416539
TIME_AT_TARGET:
> 2012-10-19 08:59:57.451094 UTC
LIGHT_TIME:
> 2.54890548

More examples can be found in here.

Disclaimer

This project is not supported or endorsed by either JPL, NAIF or NASA. The code is provided “as is”, use at your own risk.