diff options
Diffstat (limited to 'fg21sim/sky.py')
| -rw-r--r-- | fg21sim/sky.py | 91 |
1 files changed, 85 insertions, 6 deletions
diff --git a/fg21sim/sky.py b/fg21sim/sky.py index 702b3d7..84eb5dd 100644 --- a/fg21sim/sky.py +++ b/fg21sim/sky.py @@ -21,6 +21,7 @@ import healpy as hp from .utils.wcs import make_wcs from .utils.fits import read_fits_healpix, write_fits_healpix +from .utils.random import spherical_uniform from .utils.units import UnitConversions as AUC @@ -44,7 +45,8 @@ class SkyPatch: to match this output size. NOTE: Due to the FITS using Fortran ordering, while Python/numpy using C ordering, therefore, the read in image/data array - has shape (ysize, xsize). + has shape ``(ysize, xsize)``, therefore, the ``self.data`` + should be reshaped to ``(ysize, xsize)`` on output. pixelsize : float The pixel size of the sky patch, will be used to determine the sky coordinates. @@ -90,20 +92,30 @@ class SkyPatch: @property def area(self): """ - The sky coverage of this patch [ deg^2 ] + The sky coverage of this patch. + Unit: [deg^2] XXX/FIXME --------- Assumed a flat sky! Consider the spherical coordination and WCS sky projection!! """ - ps = self.pixelsize * AUC.arcsec2deg # [deg] - size = self.xsize * self.ysize - return size * ps**2 + lonsize, latsize = self.size + return lonsize * latsize @property def size(self): - return (self.xsize, self.ysize) + """ + The sky patch size along X/longitude and Y/latitude axes. + + Returns + ------- + (lonsize, latsize) : float tuple + Longitudinal and latitudinal sizes + Unit: [deg] + """ + return (self.xsize * self.pixelsize * AUC.arcsec2deg, + self.ysize * self.pixelsize * AUC.arcsec2deg) @property def shape(self): @@ -116,6 +128,36 @@ class SkyPatch: def center(self): return (self.xcenter, self.ycenter) + @property + def lon_limit(self): + """ + The longitudinal (X axis) limits. + + Returns + ------- + (lon_min, lon_max) : float tuple + The minimum and maximum longitudes (X axis). + Unit: [deg] + """ + lonsize, latsize = self.size + return (self.xcenter - 0.5*lonsize, + self.xcenter + 0.5*lonsize) + + @property + def lat_limit(self): + """ + The latitudinal (Y axis) limits. + + Returns + ------- + (lat_min, lat_max) : float tuple + The minimum and maximum latitudes (Y axis). + Unit: [deg] + """ + lonsize, latsize = self.size + return (self.ycenter - 0.5*latsize, + self.ycenter + 0.5*latsize) + def read(self, infile, frequency=None): """ Read input sky data from file. @@ -173,6 +215,7 @@ class SkyPatch: if outdir and (not os.path.exists(outdir)): os.makedirs(outdir) logger.info("Created output directory: %s" % outdir) + # NOTE: output image shape be (ysize, xsize)! image = self.data.reshape(self.ysize, self.xsize) if hasattr(self, "header"): header = self.header.copy(strip=True) @@ -277,6 +320,25 @@ class SkyPatch: else: return reprojected + def random_points(self, n=1): + """ + Generate uniformly distributed random points within the sky patch. + + Returns + ------- + lon : float, or 1D `~numpy.ndarray` + Longitudes (Galactic/equatorial); + Unit: [deg] + lat : float, or 1D `~numpy.ndarray` + Latitudes (Galactic/equatorial); + Unit: [deg] + """ + lon_min, lon_max = self.lon_limit + lat_min, lat_max = self.lat_limit + lon = np.random.uniform(low=lon_min, high=lon_max, size=n) + lat = np.random.uniform(low=lat_min, high=lat_max, size=n) + return (lon, lat) + class SkyHealpix: """ @@ -444,6 +506,23 @@ class SkyHealpix: else: return reprojected + def random_points(self, n=1): + """ + Generate uniformly distributed random points within the sky + (i.e., all sky; on an unit sphere). + + Returns + ------- + lon : float, or 1D `~numpy.ndarray` + Longitudes (Galactic/equatorial), [0, 360) [deg]. + lat : float, or 1D `~numpy.ndarray` + Latitudes (Galactic/equatorial), [-90, 90] [deg]. + """ + theta, phi = spherical_uniform(n) + lon = np.degrees(phi) + lat = 90.0 - np.degrees(theta) + return (lon, lat) + def get_sky(configs): """ |