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ICGEM Functions

Functions and types for discovering and downloading spherical harmonic gravity models from the International Centre for Global Earth Models (ICGEM).

All functions are available via brahe.datasets.icgem.<function_name>.

Loading a downloaded model into a propagator

To use an ICGEM model as the central-body field in a numerical propagator, build a GravityModelType from the same (body, name) pair via GravityModelType.icgem. The download and cache happen transparently on first use.

list_models

icgem_list_models builtin 

icgem_list_models(body: str) -> list[ICGEMIndexEntry]

List ICGEM models for a body.

Parameters:

Name Type Description Default
body str

Body name. Known: "earth", "moon", "mars", "venus", "ceres". Any other name is treated as a custom celestial body and matched against the ICGEM celestial catalog.

 required

Returns:

Type Description
list[ICGEMIndexEntry]

list[ICGEMIndexEntry]

download_model

icgem_download_model builtin 

icgem_download_model(body: str, name: str, output_path: str = None) -> str

Download a .gfc file from ICGEM (with caching).

Parameters:

Name Type Description Default
body str

Body name.

 required
name str

Model name, optionally suffixed with -DEGREE.

 required
output_path str

Optional copy destination.

 None

Returns:

Name Type Description
str str

Path to the resulting .gfc file.

refresh_index

icgem_refresh_index builtin 

icgem_refresh_index(body) -> Any

Force-refresh the ICGEM index file for a single body.

refresh_all_indexes

icgem_refresh_all_indexes builtin 

icgem_refresh_all_indexes() -> Any

Force-refresh both Earth and celestial index files.

ICGEMIndexEntry

ICGEMIndexEntry 

ICGEMIndexEntry()

One ICGEM model index row.

Initialize instance.

body property 

body: Any

Body string (e.g. "Earth", "Moon", "pluto").

degree property 

degree: Any

Maximum spherical harmonic degree.

download_path property 

download_path: Any

ICGEM relative download path (includes the opaque hash).

name property 

name: Any

Model name.

year property 

year: int

Publication year, if known.

See Also