def from_regions(cls, regions, **kwargs):
"""Create region geom from list of regions
The regions are combined with union to a compound region.
Parameters
----------
regions : list of `~regions.SkyRegion` or str
Regions
**kwargs: dict
Keyword arguments forwarded to `RegionGeom`
Returns
-------
geom : `RegionGeom`
Region map geometry
"""
if isinstance(regions, str):
regions = Regions.parse(data=regions, format="ds9")
elif isinstance(regions, SkyRegion):
regions = [regions]
elif isinstance(regions, SkyCoord):
regions = [PointSkyRegion(center=regions)]
if regions:
regions = regions_to_compound_region(regions)
return cls(region=regions, **kwargs)
def test_compound_region_center():
regions_ds9 = ("galactic;"
"circle(1,1,0.1);"
"circle(-1,1,0.1);"
"circle(1,-1,0.1);"
"circle(-1,-1,0.1);")
regions = Regions.parse(regions_ds9, format="ds9")
region = regions_to_compound_region(regions)
center = compound_region_center(region)
assert_allclose(center.galactic.l.wrap_at("180d"), 0 * u.deg, atol=1e-6)
assert_allclose(center.galactic.b, 0 * u.deg, atol=1e-6)
def from_hdulist(cls, hdulist, format="ogip", hdu=None):
"""Read region table and convert it to region list.
Parameters
----------
hdulist : `~astropy.io.fits.HDUList`
HDU list
format : {"ogip", "ogip-arf", "gadf"}
HDU format
Returns
-------
geom : `RegionGeom`
Region map geometry
"""
region_hdu = "REGION"
if format == "gadf" and hdu:
region_hdu = hdu + "_" + region_hdu
if region_hdu in hdulist:
region_table = Table.read(hdulist[region_hdu])
wcs = WcsGeom.from_header(region_table.meta).wcs
regions = []
for reg in Regions.parse(data=region_table, format="fits"):
# TODO: remove workaround once regions issue with fits serialization is sorted out
# see https://github.com/astropy/regions/issues/400
reg.meta["include"] = True
regions.append(reg.to_sky(wcs))
region = regions_to_compound_region(regions)
else:
region, wcs = None, None
if format == "ogip":
hdu_bands = "EBOUNDS"
elif format == "ogip-arf":
hdu_bands = "SPECRESP"
elif format == "gadf":
hdu_bands = hdu + "_BANDS"
else:
raise ValueError(f"Unknown format {format}")
axes = MapAxes.from_table_hdu(hdulist[hdu_bands], format=format)
return cls(region=region, wcs=wcs, axes=axes)