CompoundSphericalSkyRegion#

class regions.CompoundSphericalSkyRegion(region1, region2, operator, meta=None, visual=None)[source]#

Bases: SphericalSkyRegion

A class that represents the logical combination of two regions in spherical sky coordinates.

Parameters:

region1SphericalSkyRegion: First spherical sky region.
region2SphericalSkyRegion: Second spherical sky region.
operatorcallable: A callable binary operator.
metaRegionMeta, optional: A dictionary that stores the meta attributes of this region.
visualRegionVisual, optional: A dictionary that stores the visual meta attributes of this region.

Attributes Summary

`bounding_circle`	Bounding circle for the spherical sky region.
`bounding_lonlat`	Bounding longitude and latitude of the spherical sky region, in the region's frame.
`frame`	Coordinate frame of the region.
`operator`
`region1`()
`region2`()

Methods Summary

`contains`(coord)	Check whether a sky coordinate falls inside the spherical sky region, excluding the boundary.
`covers`(coord)	Check whether a sky coordinate falls inside the spherical sky region, including the boundary.
`discretize_boundary`([n_points])	Discretize the boundary into a `PolygonSphericalSkyRegion`, as an approximation where all sides follow great circles.
`to_pixel`(wcs[, ...])	Convert to a planar `PixelRegion`.
`to_sky`([wcs, include_boundary_distortions, ...])	Convert to a planar `SkyRegion`.
`transform_to`(frame[, merge_attributes])	Transform the `SphericalSkyRegion` instance into another instance with a different coordinate reference frame.

Attributes Documentation

bounding_circle#

bounding_lonlat#

frame#

operator#

region1#

region2#

Methods Documentation

contains(coord)[source]#

Check whether a sky coordinate falls inside the spherical sky region, excluding the boundary.

This method considers points on the boundary as outside the region, consistent with Shapely’s contains function and DE-9IM semantics.

Parameters:

coordSkyCoord: The position or positions to check.

See also

contains: Check if points are strictly inside (excludes boundary).

discretize_boundary(n_points=100)[source]#

Discretize the boundary into a PolygonSphericalSkyRegion, as an approximation where all sides follow great circles.

Parameters:

n_pointsint, optional: Number of points along the region’s boundary. Default is 100.

Returns:

poly_sky_region: PolygonSphericalSkyRegion: Spherical sky polygon object.

to_pixel(wcs, include_boundary_distortions=False, n_points=None)[source]#

Convert to a planar PixelRegion.

Parameters:

wcsWCS: The world coordinate system transformation to use to convert between sky and pixel coordinates.
include_boundary_distortionsbool, optional: If True, accounts for boundary distortions in spherical to planar conversions, by discretizing the boundary and converting the boundary polygon. Default is False, which converts to an equivalent idealized shape.
n_pointsint, optional: The number of polygon vertices for boundary discretization. This keyword will have no effect unless include_boundary_distortions=True. Default is 100.

Returns:

pixel_regionPixelRegion: A pixel region, with an equivalent shape (if include_boundary_distortions is False), or a discretized polygon of the boundary (if include_boundary_distortions is True).

to_sky(wcs=None, include_boundary_distortions=False, n_points=None)[source]#

Convert to a planar SkyRegion.

Parameters:

wcsWCS, optional: The world coordinate system transformation to use to convert between sky and pixel coordinates. Required if transforming with boundary distortions (if include_boundary_distortions is True). Ignored if boundary distortions not included.
include_boundary_distortionsbool, optional: If True, accounts for boundary distortions in spherical to planar conversions, by discretizing the boundary and converting the boundary polygon. Default is False, which converts to an equivalent idealized shape.
n_pointsint, optional: The number of polygon vertices for boundary discretization. This keyword will have no effect unless include_boundary_distortions=True. Default is 100.

Returns:

sky_regionSkyRegion: A planar sky region, with an equivalent shape (if include_boundary_distortions is False), or a discretized polygon of the boundary (if include_boundary_distortions is True).

transform_to(frame, merge_attributes=True)[source]#

Transform the SphericalSkyRegion instance into another instance with a different coordinate reference frame.

The precise frame transformed to depends on merge_attributes. If False, the destination frame is used exactly as passed in. But this is often not quite what one wants. E.g., suppose one wants to transform an ICRS coordinate that has an obstime attribute to FK4; in this case, one likely would want to use this information. Thus, the default for merge_attributes is True, in which the precedence is as follows: (1) explicitly set (i.e., non-default) values in the destination frame; (2) explicitly set values in the source; (3) default value in the destination frame.

Note that in either case, any explicitly set attributes on the source astropy.coordinates.SkyCoord that are not part of the destination frame’s definition are kept (stored on the resulting astropy.coordinates.SkyCoord), and thus one can round-trip (e.g., from FK4 to ICRS to FK4 without losing obstime).

Parameters:

framestr, or BaseCoordinateFrame class or instance: The frame to transform this coordinate into.
merge_attributesbool, optional: Whether the default attributes in the destination frame are allowed to be overridden by explicitly set attributes in the source (see note above; default: True).

Returns:

sph_sky_regionSphericalSkyRegion: A new spherical sky region represented in the frame frame.