region_to_aperture

photutils.aperture.region_to_aperture(region)

Convert a given regions.Region object to an Aperture object.

Parameters:

regionregions.Region

A supported regions.Region object.

Returns:

apertureAperture

An equivalent photutils aperture.

Raises:

TypeError

The given regions.Region object is not supported.

Notes

The ellipse width and height region parameters represent the full extent of the shapes and thus are divided by 2 when converting to elliptical aperture objects, which are defined using the semi-major (a) and semi-minor (b) axes. The width and height parameters are mapped to the semi-major (a) and semi-minor (b) axes parameters, respectively, of the elliptical apertures.

The region angle for sky-based regions is defined as the angle of the width axis relative to WCS longitude axis (PA=90). However, the sky-based apertures define the theta as the position angle of the semimajor axis relative to the North celestial pole (PA=0). Therefore, for sky-based regions the region angle is converted to the aperture theta parameter by subtracting 90 degrees.

The following regions.Region objects are supported, shown with their equivalent Aperture object:

• CirclePixelRegion ➞ CircularAperture

• CircleSkyRegion ➞ SkyCircularAperture

• EllipsePixelRegion ➞ EllipticalAperture

• EllipseSkyRegion ➞ SkyEllipticalAperture

• RectanglePixelRegion ➞ RectangularAperture

• RectangleSkyRegion ➞ SkyRectangularAperture

• CircleAnnulusPixelRegion ➞ CircularAnnulus

• CircleAnnulusSkyRegion ➞ SkyCircularAnnulus

• EllipseAnnulusPixelRegion ➞ EllipticalAnnulus

• EllipseAnnulusSkyRegion ➞ SkyEllipticalAnnulus

• RectangleAnnulusPixelRegion ➞ RectangularAnnulus

• RectangleAnnulusSkyRegion ➞ SkyRectangularAnnulus

Examples

>>> from regions import CirclePixelRegion, PixCoord
>>> from photutils.aperture import region_to_aperture
>>> region = CirclePixelRegion(center=PixCoord(x=10, y=20), radius=5)
>>> aperture = region_to_aperture(region)
>>> aperture
<CircularAperture([10., 20.], r=5.0)>