def test_polar_stereographic_a_operation__defaults():
aeaop = PolarStereographicAConversion(90)
assert aeaop.name == "unknown"
assert aeaop.method_name == "Polar Stereographic (variant A)"
assert _to_dict(aeaop) == {
"Latitude of natural origin": 90.0,
"Longitude of natural origin": 0.0,
"False easting": 0.0,
"False northing": 0.0,
"Scale factor at natural origin": 1.0,
}
def test_polar_stereographic_a_operation():
aeaop = PolarStereographicAConversion(
latitude_natural_origin=-90,
longitude_natural_origin=2,
false_easting=3,
false_northing=4,
scale_factor_natural_origin=0.5,
)
assert aeaop.name == "unknown"
assert aeaop.method_name == "Polar Stereographic (variant A)"
assert _to_dict(aeaop) == {
"Latitude of natural origin": -90.0,
"Longitude of natural origin": 2.0,
"False easting": 3.0,
"False northing": 4.0,
"Scale factor at natural origin": 0.5,
}
def _polar_stereographic(cf_params):
"""
http://cfconventions.org/cf-conventions/cf-conventions.html#polar-stereographic
"""
if "standard_parallel" in cf_params:
return PolarStereographicBConversion(
latitude_standard_parallel=cf_params["standard_parallel"],
longitude_origin=cf_params["straight_vertical_longitude_from_pole"],
false_easting=cf_params.get("false_easting", 0.0),
false_northing=cf_params.get("false_northing", 0.0),
)
return PolarStereographicAConversion(
latitude_natural_origin=cf_params["latitude_of_projection_origin"],
longitude_natural_origin=cf_params["straight_vertical_longitude_from_pole"],
false_easting=cf_params.get("false_easting", 0.0),
false_northing=cf_params.get("false_northing", 0.0),
scale_factor_natural_origin=cf_params.get(
"scale_factor_at_projection_origin", 1.0
),
)
def test_polar_stereographic_a():
crs = ProjectedCRS(conversion=PolarStereographicAConversion(90, 1, 2, 3))
expected_cf = {
"semi_major_axis": 6378137.0,
"semi_minor_axis": crs.ellipsoid.semi_minor_metre,
"inverse_flattening": crs.ellipsoid.inverse_flattening,
"reference_ellipsoid_name": "WGS 84",
"longitude_of_prime_meridian": 0.0,
"prime_meridian_name": "Greenwich",
"horizontal_datum_name": "World Geodetic System 1984",
"grid_mapping_name": "polar_stereographic",
"latitude_of_projection_origin": 90.0,
"straight_vertical_longitude_from_pole": 1.0,
"false_easting": 2.0,
"false_northing": 3.0,
"scale_factor_at_projection_origin": 1.0,
}
cf_dict = crs.to_cf()
assert cf_dict.pop("crs_wkt").startswith("PROJCRS[")
assert cf_dict == expected_cf
# test roundtrip
_test_roundtrip(expected_cf, "PROJCRS[")