Source code for astroquery.vo_conesearch.core

# 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 (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. 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.Table`. 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.Table` 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.""" if isinstance(radius, Number): sr = radius else: sr = commons.radius_to_unit(radius) return sr 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()