117 lines
3.6 KiB
Python
117 lines
3.6 KiB
Python
"""
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This module is for building datums to be used when
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building a CRS.
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"""
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from typing import Any, Dict, Optional, Union
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from pyproj._crs import Datum, Ellipsoid, PrimeMeridian
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class CustomDatum(Datum):
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"""
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.. versionadded:: 2.5.0
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Class to build a datum based on an ellipsoid and prime meridian.
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"""
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def __new__(
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cls,
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name: str = "undefined",
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ellipsoid: Any = "WGS 84",
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prime_meridian: Any = "Greenwich",
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):
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"""
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Parameters
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----------
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name: str, optional
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Name of the datum. Default is 'undefined'.
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ellipsoid: Any, optional
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Anything accepted by :meth:`pyproj.crs.Ellipsoid.from_user_input`
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or a :class:`pyproj.crs.datum.CustomEllipsoid`.
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prime_meridian: Any, optional
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Anything accepted by :meth:`pyproj.crs.PrimeMeridian.from_user_input`.
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"""
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datum_json = {
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"$schema": "https://proj.org/schemas/v0.2/projjson.schema.json",
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"type": "GeodeticReferenceFrame",
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"name": name,
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"ellipsoid": Ellipsoid.from_user_input(ellipsoid).to_json_dict(),
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"prime_meridian": PrimeMeridian.from_user_input(
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prime_meridian
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).to_json_dict(),
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}
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return cls.from_json_dict(datum_json)
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class CustomEllipsoid(Ellipsoid):
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"""
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.. versionadded:: 2.5.0
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Class to build a custom ellipsoid.
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"""
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def __new__(
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cls,
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name: str = "undefined",
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semi_major_axis: Optional[float] = None,
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inverse_flattening: Optional[float] = None,
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semi_minor_axis: Optional[float] = None,
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radius: Optional[float] = None,
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):
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"""
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Parameters
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----------
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name: str, optional
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Name of the ellipsoid. Default is 'undefined'.
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semi_major_axis: float, optional
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The semi major axis in meters. Required if missing radius.
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inverse_flattening: float, optional
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The inverse flattening in meters.
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Required if missing semi_minor_axis and radius.
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semi_minor_axis: float, optional
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The semi minor axis in meters.
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Required if missing inverse_flattening and radius.
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radius: float, optional
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The radius in meters. Can only be used alone.
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Cannot be mixed with other parameters.
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"""
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ellipsoid_json = {
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"$schema": "https://proj.org/schemas/v0.2/projjson.schema.json",
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"type": "Ellipsoid",
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"name": name,
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} # type: Dict[str, Union[float, str]]
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if semi_major_axis is not None:
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ellipsoid_json["semi_major_axis"] = semi_major_axis
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if inverse_flattening is not None:
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ellipsoid_json["inverse_flattening"] = inverse_flattening
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if semi_minor_axis is not None:
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ellipsoid_json["semi_minor_axis"] = semi_minor_axis
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if radius is not None:
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ellipsoid_json["radius"] = radius
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return cls.from_json_dict(ellipsoid_json)
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class CustomPrimeMeridian(PrimeMeridian):
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"""
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.. versionadded:: 2.5.0
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Class to build a prime meridian based on a longitude.
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"""
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def __new__(cls, longitude: float, name: str = "undefined"):
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"""
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Parameters
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----------
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longitude: float
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Longitude of prime meridian.
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name: str, optional
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Name of the prime meridian.
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"""
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datum_json = {
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"$schema": "https://proj.org/schemas/v0.2/projjson.schema.json",
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"type": "PrimeMeridian",
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"name": name,
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"longitude": longitude,
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}
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return cls.from_json_dict(datum_json)
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