def _horizontal_datum_from_params(cf_params):
# step 1: build ellipsoid
ellipsoid = None
ellipsoid_name = cf_params.get("reference_ellipsoid_name")
try:
ellipsoid = CustomEllipsoid(
name=ellipsoid_name or "undefined",
semi_major_axis=cf_params.get("semi_major_axis"),
semi_minor_axis=cf_params.get("semi_minor_axis"),
inverse_flattening=cf_params.get("inverse_flattening"),
radius=cf_params.get("earth_radius"),
)
except CRSError:
if ellipsoid_name:
ellipsoid = Ellipsoid.from_name(ellipsoid_name)
# step 2: build prime meridian
prime_meridian = None
prime_meridian_name = cf_params.get("prime_meridian_name")
try:
prime_meridian = CustomPrimeMeridian(
name=prime_meridian_name or "undefined",
longitude=cf_params["longitude_of_prime_meridian"],
)
except KeyError:
if prime_meridian_name:
prime_meridian = PrimeMeridian.from_name(prime_meridian_name)
# step 3: build datum
datum_name = cf_params.get("horizontal_datum_name")
if ellipsoid or prime_meridian:
return CustomDatum(
name=datum_name or "undefined",
ellipsoid=ellipsoid or "WGS 84",
prime_meridian=prime_meridian or "Greenwich",
)
if datum_name:
return Datum.from_name(datum_name)
return None
def test_custom_prime_meridian__name():
pm = CustomPrimeMeridian(longitude=1, name="frank")
assert pm.name == "frank"
assert pm.longitude == 1
def test_custom_prime_meridian():
pm = CustomPrimeMeridian(longitude=2)
assert pm.name == "undefined"
assert pm.longitude == 2