__all__ = ("HealpixSDSSSlicer",)
from functools import wraps
import matplotlib.path as mplPath
import numpy as np
from rubin_scheduler.utils import _xyz_from_ra_dec, gnomonic_project_toxy
from rubin_sim.maf.plots import HealpixSDSSSkyMap
from .healpix_slicer import HealpixSlicer
[docs]
class HealpixSDSSSlicer(HealpixSlicer):
"""For use with SDSS stripe 82 square images"""
def __init__(
self,
nside=128,
lon_col="RA1",
lat_col="Dec1",
verbose=True,
use_cache=True,
radius=17.0 / 60.0,
leafsize=100,
**kwargs,
):
"""Using one corner of the chip as the spatial key and the
diagonal as the radius."""
super().__init__(
verbose=verbose,
lon_col=lon_col,
lat_col=lat_col,
radius=radius,
leafsize=leafsize,
use_cache=use_cache,
nside=nside,
)
self.cornerLables = ["RA1", "Dec1", "RA2", "Dec2", "RA3", "Dec3", "RA4", "Dec4"]
self.plot_funcs = [
HealpixSDSSSkyMap,
]
[docs]
def setup_slicer(self, sim_data, maps=None):
"""
Use sim_data[self.lon_col] and sim_data[self.lat_col]
(in radians) to set up KDTree.
"""
self._run_maps(maps)
self._build_tree(sim_data[self.lon_col], sim_data[self.lat_col], self.leafsize)
self._set_rad(self.radius)
self.corners = sim_data[self.cornerLables]
@wraps(self._slice_sim_data)
def _slice_sim_data(islice):
"""Return indexes for relevant opsim data at slice_point
(slice_point=lon_col/lat_col value .. usually ra/dec)."""
sx, sy, sz = _xyz_from_ra_dec(self.slice_points["ra"][islice], self.slice_points["dec"][islice])
# Query against tree.
initIndices = self.opsimtree.query_ball_point((sx, sy, sz), self.rad)
# Loop through all the images and check if the slice_point
# is inside the corners of the chip
indices = []
# Gnomic project all the corners that are near the slice point,
# centered on slice point
x1, y1 = gnomonic_project_toxy(
self.corners["RA1"][initIndices],
self.corners["Dec1"][initIndices],
self.slice_points["ra"][islice],
self.slice_points["dec"][islice],
)
x2, y2 = gnomonic_project_toxy(
self.corners["RA2"][initIndices],
self.corners["Dec2"][initIndices],
self.slice_points["ra"][islice],
self.slice_points["dec"][islice],
)
x3, y3 = gnomonic_project_toxy(
self.corners["RA3"][initIndices],
self.corners["Dec3"][initIndices],
self.slice_points["ra"][islice],
self.slice_points["dec"][islice],
)
x4, y4 = gnomonic_project_toxy(
self.corners["RA4"][initIndices],
self.corners["Dec4"][initIndices],
self.slice_points["ra"][islice],
self.slice_points["dec"][islice],
)
for i, ind in enumerate(initIndices):
# Use matplotlib to make a polygon on
bbPath = mplPath.Path(
np.array(
[
[x1[i], y1[i]],
[x2[i], y2[i]],
[x3[i], y3[i]],
[x4[i], y4[i]],
[x1[i], y1[i]],
]
)
)
# Check if the slice_point is inside the image corners
# and append to list if it is
if bbPath.contains_point((0.0, 0.0)) == 1:
indices.append(ind)
return {
"idxs": indices,
"slice_point": {
"sid": self.slice_points["sid"][islice],
"ra": self.slice_points["ra"][islice],
"dec": self.slice_points["dec"][islice],
},
}
setattr(self, "_slice_sim_data", _slice_sim_data)
