In [1]:

    

%matplotlib inline
import numpy as np
from mocpy import MOC

from astropy.wcs.utils import skycoord_to_pixel

import astropy.units as u
from astropy.coordinates import SkyCoord, Angle

from matplotlib.path import Path
from matplotlib.patches import PathPatch


    

In [2]:

    

order=7

fits_path = '../resources/P-GALEXGR6-AIS-FUV.fits'
moc = MOC.from_fits(fits_path)
moc = moc.degrade_to_order(order)


    

In [3]:

    

# Computing time is related to the number of ipixels located in borders of the MOC.
# GALEX has a lot of holes and therefore there are a lot of ipixels lying in its border.
# It's especially true for deeper orders.

# The step taking the most of time is the construction of the graph from the coordinates of the ipixels
# lying in the border of all the dissociated MOC components.

# For the purpose of the demo we reduce the order of GALEX from 8 to 7
%time boundaries_l = moc.get_boundaries()


    

    




/home/baumann/.local/lib/python3.6/site-packages/astropy_healpix/core.py:592: RuntimeWarning: invalid value encountered in neighbours_nested
  return np.stack(func(healpix_index, nside))






    




CPU times: user 1.57 s, sys: 16.4 ms, total: 1.58 s
Wall time: 1.58 s

In [4]:

    

def get_cmap(n, name='hsv'):
    '''Returns a function that maps each index in 0, 1, ..., n-1 to a distinct 
    RGB color; the keyword argument name must be a standard mpl colormap name.'''
    return plt.cm.get_cmap(name, n)

def add_patch_path(ax, wcs, coords, **kw_mpl_pathpatch):
    xp, yp = skycoord_to_pixel(coords=coords, wcs=wcs)
    xp = xp.flatten()
    yp = yp.flatten()
    codes = np.ones(shape=(xp.shape[0]+1,))*Path.LINETO
    codes[0] = Path.MOVETO
    codes[-1] = Path.CLOSEPOLY

    vertices = np.vstack((xp, yp)).T.tolist()
    vertices.append(vertices[0])

    path = Path(vertices, codes)

    patch = PathPatch(path, **kw_mpl_pathpatch)
    ax.add_patch(patch)


    

In [9]:

    

import matplotlib.pyplot as plt
fig = plt.figure(111, figsize=(15, 15))

from mocpy import WCS

from astropy.coordinates import Angle

cmap = get_cmap(100)

with WCS(fig, 
         fov=330 * u.deg,
         center=SkyCoord(0, 0, unit='deg', frame='galactic'),
         coordsys="galactic",
         rotation=Angle(0, u.degree),
         projection="AIT") as wcs:
    ax = fig.add_subplot(1, 1, 1, projection=wcs)

    moc.fill(ax=ax, wcs=wcs, alpha=0.5, fill=True, color="r")
    # Draw the borders, each plotted in a different color.
    for border_coords in boundaries_l:
        add_patch_path(ax=ax, wcs=wcs, coords=border_coords,
                    fill=False, color=cmap(np.random.randint(100)))
    
plt.xlabel('ra')
plt.ylabel('dec')
plt.title('P-GALEXGR6-AIS-FUV with all its borders')
plt.grid(color="black", linestyle="dotted")
# The lines cutting the MOC are borders passing from the extreme east to the extreme west of the projection
plt.show()


    

    




WARNING: FITSFixedWarning: The WCS transformation has more axes (2) than the image it is associated with (0) [astropy.wcs.wcs]
WARNING: FITSFixedWarning: The WCS transformation has more axes (2) than the image it is associated with (0) [astropy.wcs.wcs]
WARNING: FITSFixedWarning: The WCS transformation has more axes (2) than the image it is associated with (0) [astropy.wcs.wcs]
WARNING: FITSFixedWarning: The WCS transformation has more axes (2) than the image it is associated with (0) [astropy.wcs.wcs]






    

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