Source code for astroquery.skyview.core

# Licensed under a 3-clause BSD style license - see LICENSE.rst
import pprint
from bs4 import BeautifulSoup
from six.moves.urllib import parse as urlparse
import six
from astropy import units as u

from . import conf
from ..query import BaseQuery
from ..utils import prepend_docstr_nosections, commons, async_to_sync


__doctest_skip__ = [
    'SkyViewClass.get_images',
    'SkyViewClass.get_images_async',
    'SkyViewClass.get_image_list']


[docs]@async_to_sync class SkyViewClass(BaseQuery): URL = conf.url def __init__(self): super(SkyViewClass, self).__init__() self._default_form_values = None def _get_default_form_values(self, form): """ Return the already selected values of a given form (a BeautifulSoup form node) as a dict. """ res = [] for elem in form.find_all(['input', 'select']): # ignore the submit and reset buttons if elem.get('type') in ['submit', 'reset']: continue # check boxes: enabled boxes have the value "on" if not specified # otherwise. Found out by debugging, perhaps not documented. if (elem.get('type') == 'checkbox' and elem.get('checked') in ["", "checked"]): value = elem.get('value', 'on') res.append((elem.get('name'), value)) # radio buttons and simple input fields if elem.get('type') == 'radio' and\ elem.get('checked') in ["", "checked"] or\ elem.get('type') in [None, 'text']: res.append((elem.get('name'), elem.get('value'))) # dropdown menu, multi-section possible if elem.name == 'select': for option in elem.find_all('option'): if option.get('selected') == '': value = option.get('value', option.text.strip()) res.append((elem.get('name'), value)) return {k: v for (k, v) in res if v not in [None, u'None', u'null'] and v } def _generate_payload(self, input=None): """ Fill out the form of the SkyView site and submit it with the values given in ``input`` (a dictionary where the keys are the form element's names and the values are their respective values). """ if input is None: input = {} form_response = self._request('GET', self.URL) bs = BeautifulSoup(form_response.content, "html.parser") form = bs.find('form') # cache the default values to save HTTP traffic if self._default_form_values is None: self._default_form_values = self._get_default_form_values(form) # only overwrite payload's values if the `input` value is not None # to avoid overwriting of the form's default values payload = self._default_form_values.copy() for k, v in six.iteritems(input): if v is not None: payload[k] = v url = urlparse.urljoin(self.URL, form.get('action')) return url, payload def _submit_form(self, input=None, cache=True): url, payload = self._generate_payload(input=input) response = self._request('GET', url, params=payload, cache=cache) return response
[docs] def get_images(self, position, survey, coordinates=None, projection=None, pixels=None, scaling=None, sampler=None, resolver=None, deedger=None, lut=None, grid=None, gridlabels=None, radius=None, height=None, width=None, cache=True, show_progress=True): """ Query the SkyView service, download the FITS file that will be found and return a generator over the local paths to the downloaded FITS files. Note that the files will be downloaded when the generator will be exhausted, i.e. just calling this method alone without iterating over the result won't issue a connection to the SkyView server. Parameters ---------- position : str Determines the center of the field to be retrieved. Both coordinates (also equatorial ones) and object names are supported. Object names are converted to coordinates via the SIMBAD or NED name resolver. See the reference for more info on the supported syntax for coordinates. survey : str or list of str Select data from one or more surveys. The number of surveys determines the number of resulting file downloads. Passing a list with just one string has the same effect as passing this string directly. coordinates : str Choose among common equatorial, galactic and ecliptic coordinate systems (``"J2000"``, ``"B1950"``, ``"Galactic"``, ``"E2000"``, ``"ICRS"``) or pass a custom string. projection : str Choose among the map projections (the value in parentheses denotes the string to be passed): Gnomonic (Tan), default value good for small regions Rectangular (Car) simplest projection Aitoff (Ait) Hammer-Aitoff, equal area projection good for all sky maps Orthographic (Sin) Projection often used in interferometry Zenith Equal Area (Zea) equal area, azimuthal projection COBE Spherical Cube (Csc) Used in COBE data Arc (Arc) Similar to Zea but not equal-area pixels : str Selects the pixel dimensions of the image to be produced. A scalar value or a pair of values separated by comma may be given. If the value is a scalar the number of width and height of the image will be the same. By default a 300x300 image is produced. scaling : str Selects the transformation between pixel intensity and intensity on the displayed image. The supported values are: ``"Log"``, ``"Sqrt"``, ``"Linear"``, ``"HistEq"``, ``"LogLog"``. sampler : str The sampling algorithm determines how the data requested will be resampled so that it can be displayed. resolver : str The name resolver allows to choose a name resolver to use when looking up a name which was passed in the ``position`` parameter (as opposed to a numeric coordinate value). The default choice is to call the SIMBAD name resolver first and then the NED name resolver if the SIMBAD search fails. deedger : str When multiple input images with different backgrounds are resampled the edges between the images may be apparent because of the background shift. This parameter makes it possible to attempt to minimize these edges by applying a de-edging algorithm. The user can elect to choose the default given for that survey, to turn de-edging off, or to use the default de-edging algorithm. The supported values are: ``"_skip_"`` to use the survey default, ``"skyview.process.Deedger"`` (for enabling de-edging), and ``"null"`` to disable. lut : str Choose from the color table selections to display the data in false color. grid : bool overlay a coordinate grid on the image if True gridlabels : bool annotate the grid with coordinates positions if True radius : `~astropy.units.Quantity` or None The radius of the specified field. Overrides width and height. width : `~astropy.units.Quantity` or None The width of the specified field. Must be specified with ``height``. height : `~astropy.units.Quantity` or None The height of the specified field. Must be specified with ``width``. References ---------- .. [1] http://skyview.gsfc.nasa.gov/current/help/fields.html Examples -------- >>> sv = SkyView() >>> paths = sv.get_images(position='Eta Carinae', ... survey=['Fermi 5', 'HRI', 'DSS']) >>> for path in paths: ... print('\tnew file:', path) Returns ------- A list of `~astropy.io.fits.HDUList` objects. """ readable_objects = self.get_images_async(position, survey, coordinates, projection, pixels, scaling, sampler, resolver, deedger, lut, grid, gridlabels, radius=radius, height=height, width=width, cache=cache, show_progress=show_progress) return [obj.get_fits() for obj in readable_objects]
[docs] @prepend_docstr_nosections(get_images.__doc__) def get_images_async(self, position, survey, coordinates=None, projection=None, pixels=None, scaling=None, sampler=None, resolver=None, deedger=None, lut=None, grid=None, gridlabels=None, radius=None, height=None, width=None, cache=True, show_progress=True): """ Returns ------- A list of context-managers that yield readable file-like objects """ image_urls = self.get_image_list(position, survey, coordinates, projection, pixels, scaling, sampler, resolver, deedger, lut, grid, gridlabels, radius=radius, height=height, width=width, cache=cache) return [commons.FileContainer(url, encoding='binary', show_progress=show_progress) for url in image_urls]
[docs] @prepend_docstr_nosections(get_images.__doc__, sections=['Returns', 'Examples']) def get_image_list(self, position, survey, coordinates=None, projection=None, pixels=None, scaling=None, sampler=None, resolver=None, deedger=None, lut=None, grid=None, gridlabels=None, radius=None, width=None, height=None, cache=True): """ Returns ------- list of image urls Examples -------- >>> SkyView().get_image_list(position='Eta Carinae', ... survey=['Fermi 5', 'HRI', 'DSS']) [u'http://skyview.gsfc.nasa.gov/tempspace/fits/skv6183161285798_1.fits', u'http://skyview.gsfc.nasa.gov/tempspace/fits/skv6183161285798_2.fits', u'http://skyview.gsfc.nasa.gov/tempspace/fits/skv6183161285798_3.fits'] """ self._validate_surveys(survey) if radius is not None: size_deg = str(radius.to(u.deg).value) elif width and height: size_deg = "{0},{1}".format(width.to(u.deg).value, height.to(u.deg).value) elif width and height: raise ValueError("Must specify width and height if you " "specify either.") else: size_deg = None input = { 'Position': parse_coordinates(position), 'survey': survey, 'Deedger': deedger, 'lut': lut, 'projection': projection, 'gridlabels': '1' if gridlabels else '0', 'coordinates': coordinates, 'scaling': scaling, 'grid': grid, 'resolver': resolver, 'Sampler': sampler, 'imscale': size_deg, 'size': size_deg, 'pixels': pixels} response = self._submit_form(input, cache=cache) urls = self._parse_response(response) return urls
def _parse_response(self, response): bs = BeautifulSoup(response.content, "html.parser") urls = [] for a in bs.find_all('a'): if a.text == 'FITS': href = a.get('href') urls.append(urlparse.urljoin(response.url, href)) return urls @property def survey_dict(self): if not hasattr(self, '_survey_dict'): response = self._request('GET', self.URL, cache=False) page = BeautifulSoup(response.content, "html.parser") surveys = page.findAll('select', {'name': 'survey'}) self._survey_dict = { sel['id']: [x.text for x in sel.findAll('option')] for sel in surveys if 'overlay' not in sel['id'] } return self._survey_dict @property def _valid_surveys(self): # Return a flat list of all valid surveys return [x for v in self.survey_dict.values() for x in v] def _validate_surveys(self, surveys): if not isinstance(surveys, list): surveys = [surveys] for sv in surveys: if sv not in self._valid_surveys: raise ValueError("Survey is not among the surveys hosted " "at skyview. See list_surveys or " "survey_dict for valid surveys.")
[docs] def list_surveys(self): """ Print out a formatted version of the survey dict """ pprint.pprint(self.survey_dict)
def parse_coordinates(position): coord = commons.parse_coordinates(position) return coord.fk5.to_string() SkyView = SkyViewClass()