astro query:docs

- Index
- Modules

### Navigation

- next »
- « previous |
- astroquery v0.4.11 »
- HiPS2fits Service (`astroquery.hips2fits`)

# HiPS2fits Service (`astroquery.hips2fits`)

## Getting started

Query the CDS hips2fits service

The CDS hips2fits service offers a way to extract FITS images from HiPS sky maps. HiPS is an IVOA standard that combines individual images in order to produce a progressive hierarchical sky map describing the whole survey. Please refer to the IVOA paper for more info.

Given an astropy user-defined WCS with a HiPS name, hips2fits will return you the corresponding FITS image (JPG/PNG output formats are also implemented).

See the list of valid HiPS names hosted in CDS here. It is also possible to use `astroquery.mocserver.MOCServerClass.find_datasets()` to retrieve the list of HiPSes matching an expression (e.g. *HST* will return the names of the HST surveys HiPSes).

This package implements two methods:

- `query_with_wcs()` extracting a FITS image from a HiPS and an astropy `wcs.WCS`.

    See here all the valid HiPS names hosted in CDS.

- `query()` extracting a FITS image from a HiPS given the output image pixel size, the center of projection, the type of projection and the field of view.

    See here all the valid HiPS names hosted in CDS.

## Examples

### With a user defined astropy WCS

    >>> from astroquery.hips2fits import hips2fits
    >>> import matplotlib.pyplot as plt
    >>> from matplotlib.colors import Colormap
    >>> from astropy import wcs as astropy_wcs
    >>> # Create a new WCS astropy object
    >>> w = astropy_wcs.WCS(header={
    ...     'NAXIS1': 2000,         # Width of the output fits/image
    ...     'NAXIS2': 1000,         # Height of the output fits/image
    ...     'WCSAXES': 2,           # Number of coordinate axes
    ...     'CRPIX1': 1000.0,       # Pixel coordinate of reference point
    ...     'CRPIX2': 500.0,        # Pixel coordinate of reference point
    ...     'CDELT1': -0.18,        # [deg] Coordinate increment at reference point
    ...     'CDELT2': 0.18,         # [deg] Coordinate increment at reference point
    ...     'CUNIT1': 'deg',        # Units of coordinate increment and value
    ...     'CUNIT2': 'deg',        # Units of coordinate increment and value
    ...     'CTYPE1': 'GLON-MOL',   # galactic longitude, Mollweide's projection
    ...     'CTYPE2': 'GLAT-MOL',   # galactic latitude, Mollweide's projection
    ...     'CRVAL1': 0.0,          # [deg] Coordinate value at reference point
    ...     'CRVAL2': 0.0,          # [deg] Coordinate value at reference point
    ... })
    >>> hips = 'CDS/P/DSS2/red'
    >>> result = hips2fits.query_with_wcs(
    ...    hips=hips,
    ...    wcs=w,
    ...    get_query_payload=False,
    ...    format='jpg',
    ...    min_cut=0.5,
    ...    max_cut=99.5,
    ...    cmap=Colormap('viridis'),
    ... )
    >>> im = plt.imshow(result)
    >>> plt.show()

Without WCS

    >>> from astroquery.hips2fits import hips2fits
    >>> import matplotlib.pyplot as plt
    >>> from matplotlib.colors import Colormap
    >>> import astropy.units as u
    >>> from astropy.coordinates import Longitude, Latitude, Angle
    >>> hips = 'CDS/P/DSS2/red'
    >>> result = hips2fits.query(
    ...    hips=hips,
    ...    width=1000,
    ...    height=500,
    ...    ra=Longitude(0 * u.deg),
    ...    dec=Latitude(20 * u.deg),
    ...    fov=Angle(80 * u.deg),
    ...    projection="AIT",
    ...    get_query_payload=False,
    ...    format='jpg',
    ...    min_cut=0.5,
    ...    max_cut=99.5,
    ...    cmap=Colormap('viridis'),
    ... )
    >>> im = plt.imshow(result)
    >>> plt.show()

## Reference/API

### astroquery.hips2fits Package

#### CDS hips2fits Query Tool

Author:

  Matthieu Baumann (matthieu.baumann@astro.unistra.fr)

This package is for querying the CDS hips2fits service, primarily hosted at:

- https://alasky.cds.unistra.fr/hips-image-services/hips2fits

- https://alaskybis.cds.unistra.fr/hips-image-services/hips2fits (mirror)

Note: If the access to hips2fits was helpful for your research work, the following acknowledgment would be appreciated:

    This research has made use of the hips2fits, a tool developed at CDS, Strasbourg, France aiming at extracting
    FITS images from HiPS sky maps with respect to a WCS.

#### Classes

`hips2fitsClass`(*args) | Query the CDS hips2fits service
`Conf`() | Configuration parameters for `astroquery.template_module`.