# Licensed under a 3-clause BSD style license - see LICENSE.rst
import urllib
import warnings
from io import BytesIO
from numbers import Number
from astropy import units as u
from astropy.coordinates import (Angle, BaseCoordinateFrame, ICRS, SkyCoord,
Longitude, Latitude)
from astropy.io.votable import table
from .exceptions import VOSError, ConeSearchError, InvalidAccessURL
from .vos_catalog import vo_tab_parse
from ..exceptions import NoResultsWarning
from ..query import BaseQuery
from ..utils import commons
# Import configurable items declared in __init__.py
from . import conf
__all__ = ['ConeSearch', 'ConeSearchClass']
__doctest_skip__ = ['ConeSearchClass']
[docs]
class ConeSearchClass(BaseQuery):
"""
The class for querying the Virtual Observatory (VO)
Cone Search web service.
Examples
--------
>>> from astropy import units as u
>>> from astropy.coordinates import SkyCoord
>>> from astroquery.vo_conesearch import ConeSearch
>>> ConeSearch.query_region(SkyCoord.from_name('M31'), 5 * u.arcsecond)
<Table masked=True length=6>
objID gscID2 ... compassGSC2id Mag
... mag
int64 object ... object float32
-------------- ---------------- ... ------------- -------
23323175812944 00424433+4116085 ... 6453800072293 --
23323175812933 00424455+4116103 ... 6453800072282 --
23323175812939 00424464+4116092 ... 6453800072288 --
23323175812931 00424464+4116106 ... 6453800072280 --
23323175812948 00424403+4116069 ... 6453800072297 --
23323175812930 00424403+4116108 ... 6453800072279 --
"""
def __init__(self):
super().__init__()
[docs]
def query_region_async(self, *args, **kwargs):
"""
This is not implemented. Use
:class:`~astroquery.vo_conesearch.conesearch.AsyncConeSearch` instead.
"""
raise NotImplementedError(
'Use astroquery.vo_conesearch.conesearch.AsyncConeSearch class.')
[docs]
def query_region(self, coordinates, radius, *, verb=1,
get_query_payload=False, cache=True, verbose=False,
service_url=None, return_astropy_table=True,
use_names_over_ids=False):
"""
Perform Cone Search and returns the result of the
first successful query.
Parameters
----------
coordinates : str, `astropy.coordinates` object, list, or tuple
Position of the center of the cone to search.
It may be specified as an object from the
:ref:`astropy:astropy-coordinates` package,
string as accepted by
:func:`~astroquery.utils.parse_coordinates`, or tuple/list.
If given as tuple or list, it is assumed to be ``(RA, DEC)``
in the ICRS coordinate frame, given in decimal degrees.
radius : float or `~astropy.units.quantity.Quantity`
Radius of the cone to search:
- If float is given, it is assumed to be in decimal degrees.
- If `~astropy.units.quantity.Quantity` is given,
it is internally converted to degrees.
verb : {1, 2, 3}, optional
Verbosity indicating how many columns are to be returned
in the resulting table. Support for this parameter by
a Cone Search service implementation is optional.
If the service supports the parameter:
1. Return the bare minimum number of columns that
the provider considers useful in describing the
returned objects.
2. Return a medium number of columns between the
minimum and maximum (inclusive) that are
considered by the provider to most typically
useful to the user.
3. Return all of the columns that are available for
describing the objects.
If not supported, the service should ignore the parameter
and always return the same columns for every request.
get_query_payload : bool, optional
Just return the dict of HTTP request parameters.
cache : bool, optional
Use caching for VO Service database. Access to actual VO
websites referenced by the database still needs internet
connection.
Defaults to True. If set overrides global caching behavior.
See :ref:`caching documentation <astroquery_cache>`.
verbose : bool, optional
Verbose output, including VO table warnings.
service_url : str or `None`
URL for the Cone Search service. If not given, will use
``fallback_url`` from ``vo_conesearch`` configuration.
return_astropy_table : bool
Returned ``result`` will be `astropy.table.Table` rather
than `astropy.io.votable.tree.TableElement`.
use_names_over_ids : bool
When `True` use the ``name`` attributes of columns as the names
of columns in the `~astropy.table.Table` instance. Since names
are not guaranteed to be unique, this may cause some columns
to be renamed by appending numbers to the end. Otherwise
(default), use the ID attributes as the column names.
Returns
-------
result : `astropy.table.Table` or `astropy.io.votable.tree.TableElement`
Table from successful VO service request.
See ``return_astropy_table`` option for the kind of table returned.
"""
request_payload = self._args_to_payload(coordinates, radius, verb)
if get_query_payload:
return request_payload
url = _validate_url(service_url)
response = self._request('GET', url, params=request_payload,
timeout=conf.timeout, cache=cache)
result = self._parse_result(response, url, pars=request_payload,
verbose=verbose)
# Convert to an astropy.table.Table object
if result is not None and return_astropy_table:
result = result.to_table(use_names_over_ids=use_names_over_ids)
result.url = url # To be consistent with votable option
return result
def _args_to_payload(self, coordinates, radius, verb):
"""
Takes the arguments from any of the query functions and returns a
dictionary that can be used as the data for an HTTP POST request.
"""
ra, dec = _validate_coord(coordinates)
sr = _validate_sr(radius)
v = _validate_verb(verb)
return {'RA': ra, 'DEC': dec, 'SR': sr, 'VERB': v}
def _parse_result(self, response, url, pars={}, verbose=False):
"""
Parse the raw HTTP response and return it as a table.
"""
# Suppress any VOTable related warnings.
if not verbose:
commons.suppress_vo_warnings()
query = []
for key, value in pars.items():
query.append('{0}={1}'.format(urllib.parse.quote(key),
urllib.parse.quote_plus(str(value))))
parsed_url = url + '&'.join(query)
# Parse the result
pedantic = 'exception' if conf.pedantic else 'warn'
tab = table.parse(BytesIO(response.content), filename=parsed_url,
verify=pedantic)
try:
result = vo_tab_parse(tab, url, pars)
except VOSError as exc:
result = None
warnings.warn(str(exc), NoResultsWarning)
return result
def _validate_url(url):
"""Validate Cone Search service URL."""
if url is None:
url = conf.fallback_url
# This is the standard expectation of a service URL
if not url.endswith(('?', '&')):
raise InvalidAccessURL("URL should end with '?' or '&'")
# && in URL can break some queries, so remove trailing & if needed
# as & will be added back later
if url.endswith('&'):
url = url[:-1]
return url
def _validate_coord(coordinates):
"""Validate coordinates and return them as ICRS RA and DEC in deg."""
if isinstance(coordinates, (list, tuple)) and len(coordinates) == 2:
icrscoord = ICRS(Longitude(coordinates[0], unit=u.degree),
Latitude(coordinates[1], unit=u.degree))
else:
c = commons.parse_coordinates(coordinates)
if isinstance(c, SkyCoord):
icrscoord = c.transform_to(ICRS).frame
elif isinstance(c, BaseCoordinateFrame):
icrscoord = c.transform_to(ICRS)
else: # Assume already ICRS
icrscoord = c
return icrscoord.ra.degree, icrscoord.dec.degree
def _validate_sr(radius):
"""Validate search radius and return value in deg."""
return radius if isinstance(radius, Number) else Angle(radius).to_value(u.deg)
def _validate_verb(verb):
"""Validate verbosity."""
try:
v = int(verb)
except ValueError:
v = 999
if v not in (1, 2, 3):
raise ConeSearchError('Verbosity must be 1, 2, or 3')
return v
ConeSearch = ConeSearchClass()