def get_lon_lat(center, theta, radius=1, resolution=100):
longitude, latitude = center
# #longitude values restricted on domain of (-180,180]
# if longitude.to_value(u.deg) > 180. :
# longitude = -360. * u.deg + longitude.to(u.deg)
# Start off by generating the circle around the North pole
lon = np.linspace(0.0, 2 * np.pi, resolution + 1)[:-1] * u.radian
# lat = np.repeat(0.5 * np.pi - radius.to_value(u.radian), resolution) * u.radian
lat = np.repeat(0.5 * np.pi - theta.to_value(u.radian), resolution) * u.radian
lon, lat = _rotate_polygon(lon, lat, longitude, latitude)
return lon, lat
def convert_to_polygon(center_ra, center_dec, radius, resolution=16):
"""
Convert a circle to a polygon
:param center_ra: astropy.units.Quantity
:param center_dec: astropy.units.Quantity
:param radius: astropy.units.Quantity
:param resolution: int
:return:
"""
lon = np.linspace(0., 2 * np.pi, resolution + 1)[:-1] * u.radian
lat = np.repeat(0.5 * np.pi - radius.to_value(u.radian),
resolution) * u.radian
lon, lat = _rotate_polygon(lon, lat, center_ra, center_dec)
lon = lon.to_value(u.deg).tolist()
lat = lat.to_value(u.deg).tolist()
return lon, lat
def __init__(self,
ra,
dec,
radius,
resolution=100,
vertex_unit=u.degree,
**kwargs):
# Extract longitude/latitude, either from a tuple of two quantities, or
# a single 2-element Quantity.
longitude, latitude = ra, dec
# #longitude values restricted on domain of (-180,180]
# if longitude.to_value(u.deg) > 180. :
# longitude = -360. * u.deg + longitude.to(u.deg)
# Start off by generating the circle around the North pole
lon = np.linspace(0.0, 2 * np.pi, resolution + 1)[:-1] * u.radian
lat = np.repeat(0.5 * np.pi - np.deg2rad(radius),
resolution) * u.radian
lon, lat = _rotate_polygon(lon, lat, longitude, latitude)
# Extract new longitude/latitude in the requested units
lon = lon.to_value(vertex_unit)
lat = lat.to_value(vertex_unit)
# Create polygon vertices
vertices = np.array([lon, lat]).transpose()
# split path into two sections if circle crosses -180, 180 bounds
codes = []
last = (4000.4 * u.degree).to_value(
vertex_unit
) # 400.4 is a random number large enough so first element is "MOVETO"
for v in vertices:
if np.absolute(v[0] - last) > (300 *
u.degree).to_value(vertex_unit):
codes.append(Path.MOVETO)
else:
codes.append(Path.LINETO)
last = v[0]
circle_path = Path(vertices, codes)
super().__init__(circle_path, **kwargs)
