Examples¶
Cone search¶
"""Demonstration of the cone_search function."""
# Astropy tools
import astropy.units as u
# For plots
import matplotlib.pyplot as plt
from astropy.coordinates import Angle, Latitude, Longitude, SkyCoord
# Moc and HEALPix tools
from cdshealpix import cone_search
from mocpy import MOC, WCS
max_depth = 10
ipix, depth, fully_covered = cone_search(
lon=Longitude(0, u.deg), lat=Latitude(0, u.deg), radius=10 * u.deg, depth=max_depth
)
moc = MOC.from_healpix_cells(ipix, depth, max_depth)
# Plot the MOC using matpl/Wordotlib
fig = plt.figure(111, figsize=(10, 10))
# Define a astropy WCS from the mocpy.WCS class
with WCS(
fig,
fov=30 * u.deg,
center=SkyCoord(0, 0, unit="deg", frame="icrs"),
coordsys="icrs",
rotation=Angle(0, u.degree),
projection="AIT",
) as wcs:
ax = fig.add_subplot(1, 1, 1, projection=wcs)
# Call fill with a matplotlib axe and the `~astropy.wcs.WCS` wcs object.
moc.fill(ax=ax, wcs=wcs, alpha=0.5, fill=True, color="green")
# Draw the perimeter of the MOC in black
moc.border(ax=ax, wcs=wcs, alpha=0.5, color="black")
plt.xlabel("ra")
plt.ylabel("dec")
plt.title("Cone search")
plt.grid(color="black", linestyle="dotted")
plt.show()
(Source code, png, hires.png, pdf)
Elliptical cone search¶
"""Illustration of the elliptical cone search functionnality."""
# Astropy tools
import astropy.units as u
# For plots
import matplotlib.pyplot as plt
from astropy.coordinates import Angle, Latitude, Longitude, SkyCoord
# Moc and HEALPix tools
from cdshealpix import elliptical_cone_search
from mocpy import MOC, WCS
max_depth = 10
ipix, depth, fully_covered = elliptical_cone_search(
lon=Longitude(0, u.deg),
lat=Latitude(0, u.deg),
a=Angle(50, unit="deg"),
b=Angle(5, unit="deg"),
pa=Angle(30, unit="deg"),
depth=max_depth,
)
moc = MOC.from_healpix_cells(ipix, depth, max_depth)
# Plot the MOC using matplotlib
fig = plt.figure(111, figsize=(10, 10))
# Define a astropy WCS easily
with WCS(
fig,
fov=100 * u.deg,
center=SkyCoord(0, 0, unit="deg", frame="icrs"),
coordsys="icrs",
rotation=Angle(0, u.degree),
projection="AIT",
) as wcs:
ax = fig.add_subplot(1, 1, 1, projection=wcs)
# Call fill with a matplotlib axe and the `~astropy.wcs.WCS` wcs object.
moc.fill(ax=ax, wcs=wcs, alpha=0.5, fill=True, color="green")
# Draw the perimeter of the MOC in black
moc.border(ax=ax, wcs=wcs, alpha=0.5, color="black")
plt.xlabel("ra")
plt.ylabel("dec")
plt.title("Elliptical cone search")
plt.grid(color="black", linestyle="dotted")
plt.show()
(Source code, png, hires.png, pdf)
Polygon search¶
"""Example for polygon HEALPix."""
# Astropy tools
import astropy.units as u
# For plots
import matplotlib.pyplot as plt
from astropy.coordinates import Angle, Latitude, Longitude, SkyCoord
# Moc and HEALPix tools
from cdshealpix import polygon_search
from mocpy import MOC, WCS
lon = Longitude([20, -20, -20, 20], u.deg)
lat = Latitude([20, 20, -20, -20], u.deg)
max_depth = 7
ipix, depth, fully_covered = polygon_search(lon, lat, max_depth)
moc = MOC.from_healpix_cells(ipix, depth, max_depth)
# Plot the MOC using matplotlib
fig = plt.figure(111, figsize=(10, 10))
# Define a astropy WCS easily
with WCS(
fig,
fov=100 * u.deg,
center=SkyCoord(0, 0, unit="deg", frame="icrs"),
coordsys="icrs",
rotation=Angle(0, u.degree),
projection="AIT",
) as wcs:
ax = fig.add_subplot(1, 1, 1, projection=wcs)
# Call fill with a matplotlib axe and the `~astropy.wcs.WCS` wcs object.
moc.fill(ax=ax, wcs=wcs, alpha=0.5, fill=True, color="green")
# Draw the perimeter of the MOC in black
moc.border(ax=ax, wcs=wcs, alpha=0.5, color="black")
plt.xlabel("ra")
plt.ylabel("dec")
plt.title("Polygon search")
plt.grid(color="black", linestyle="dotted")
plt.show()
(Source code, png, hires.png, pdf)
