TAP/TAP+ (astroquery.utils.tap)

Table Access Protocol (TAP: http://www.ivoa.net/documents/TAP/) specified by the International Virtual Observatory Alliance (IVOA: http://www.ivoa.net) defines a service protocol for accessing general table data.

TAP+ is the ESAC Space Data Centre (ESDC: http://www.cosmos.esa.int/web/esdc/) extension of the Table Access Protocol.

The TAP query language is Astronomical Data Query Language (ADQL: http://www.ivoa.net/documents/ADQL/2.0), which is similar to Structured Query Language (SQL), widely used to query databases.

TAP provides two operation modes: Synchronous and Asynchronous:

  • Synchronous: the response to the request will be generated as soon as the request received by the server. (Do not use this method for queries that generate a big amount of results.)
  • Asynchronous: the server will start a job that will execute the request. The first response to the request is the required information (a link) to obtain the job status. Once the job is finished, the results can be retrieved.

TAP+ is fully compatible with TAP specification. TAP+ adds more capabilities like authenticated access and persistent user storage area.

Please, check methods documentation to determine whether a method is TAP compatible.

Examples

1. Non authenticated access

1.1 Getting public tables

To load only table names (TAP+ capability)

>>> from astroquery.utils.tap.core import TapPlus
>>>
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> tables = gaia.load_tables(only_names=True)
>>> for table in (tables):
>>>   print(table.get_qualified_name())

public.dual
public.tycho2
public.igsl_source
public.hipparcos
public.hipparcos_newreduction
public.hubble_sc
public.igsl_source_catalog_ids
tap_schema.tables
tap_schema.keys
tap_schema.columns
tap_schema.schemas
tap_schema.key_columns
gaiadr1.phot_variable_time_series_gfov
gaiadr1.ppmxl_neighbourhood
gaiadr1.gsc23_neighbourhood
gaiadr1.ppmxl_best_neighbour
gaiadr1.sdss_dr9_neighbourhood
...
gaiadr1.tgas_source
gaiadr1.urat1_original_valid
gaiadr1.allwise_original_valid

To load table names (TAP compatible)

>>> from astroquery.utils.tap.core import TapPlus
>>>
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> tables = gaia.load_tables()
>>> for table in (tables):
>>>   print(table.get_qualified_name())

public.dual
public.tycho2
public.igsl_source
public.hipparcos
public.hipparcos_newreduction
public.hubble_sc
public.igsl_source_catalog_ids
tap_schema.tables
tap_schema.keys
tap_schema.columns
tap_schema.schemas
tap_schema.key_columns
gaiadr1.phot_variable_time_series_gfov
gaiadr1.ppmxl_neighbourhood
gaiadr1.gsc23_neighbourhood
gaiadr1.ppmxl_best_neighbour
gaiadr1.sdss_dr9_neighbourhood
...
gaiadr1.tgas_source
gaiadr1.urat1_original_valid
gaiadr1.allwise_original_valid

To load only a table (TAP+ capability)

>>> from astroquery.utils.tap.core import TapPlus
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> table = gaia.load_table('gaiadr1.gaia_source')
>>> print(table)

Table name: gaiadr1.gaia_source
Description: This table has an entry for every Gaia observed source as listed in the
Main Database accumulating catalogue version from which the catalogue
release has been generated. It contains the basic source parameters,
that is only final data (no epoch data) and no spectra (neither final
nor epoch).
Num. columns: 57

Once a table is loaded, columns can be inspected

>>> from astroquery.utils.tap.core import TapPlus
>>>
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> table = gaia.load_table('gaiadr1.gaia_source')
>>> for column in (gaiadr1_table.get_columns()):
>>>   print(column.get_name())

solution_id
source_id
random_index
ref_epoch
ra
ra_error
dec
dec_error
...
ecl_lon
ecl_lat

1.2 Synchronous query

A synchronous query will not store the results at server side. These queries must be used when the amount of data to be retrieve is ‘small’.

There is a limit of 2000 rows. If you need more than that, you must use asynchronous queries.

The results can be saved in memory (default) or in a file.

Query without saving results in a file:

>>> from astroquery.utils.tap.core import TapPlus
>>>
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>>
>>> job = gaia.launch_job("select top 100 \
>>> solution_id,ref_epoch,ra_dec_corr,astrometric_n_obs_al,matched_observations,duplicated_source,phot_variable_flag \
>>> from gaiadr1.gaia_source order by source_id")
>>>
>>> print(job)

Jobid: None
Phase: COMPLETED
Owner: None
Output file: sync_20170223111452.xml.gz
Results: None

>>> r = job.get_results()
>>> print(r['solution_id'])

  solution_id
-------------------
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
              ...
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
Length = 100 rows

Query saving results in a file:

>>> from astroquery.utils.tap.core import TapPlus
>>>
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> job = gaia.launch_job("select top 100 \
>>> solution_id,ref_epoch,ra_dec_corr,astrometric_n_obs_al,matched_observations,duplicated_source,phot_variable_flag \
>>> from gaiadr1.gaia_source order by source_id", dump_to_file=True)
>>>
>>> print(job)

Jobid: None
Phase: COMPLETED
Owner: None
Output file: sync_20170223111452.xml.gz
Results: None

>>> r = job.get_results()
>>> print(r['solution_id'])

  solution_id
-------------------
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
              ...
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
Length = 100 rows

1.3 Synchronous query on an ‘on-the-fly’ uploaded table

A table can be uploaded to the server in order to be used in a query.

>>> from astroquery.utils.tap.core import TapPlus
>>>
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>>
>>> upload_resource = 'my_table.xml'
>>> j = gaia.launch_job(query="select * from tap_upload.table_test", upload_resource=upload_resource, \
>>> upload_table_name="table_test", verbose=True)
>>> r = j.get_results()
>>> r.pprint()

source_id alpha delta
--------- ----- -----
        a   1.0   2.0
        b   3.0   4.0
        c   5.0   6.0

1.4 Asynchronous query

Asynchronous queries save results at server side. These queries can be accessed at any time. For anonymous users, results are kept for three days.

The results can be saved in memory (default) or in a file.

Query without saving results in a file:

>>> from astroquery.utils.tap.core import TapPlus
>>>
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> job = gaia.launch_job_async("select top 100 * from gaiadr1.gaia_source order by source_id")
>>>
>>> print(job)

Jobid: 1487845273526O
Phase: COMPLETED
Owner: None
Output file: async_20170223112113.vot
Results: None

>>> r = job.get_results()
>>> print(r['solution_id'])

  solution_id
-------------------
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
              ...
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
Length = 100 rows

Query saving results in a file:

>>> from astroquery.utils.tap.core import TapPlus
>>>
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> job = gaia.launch_job_async("select top 100 * from gaiadr1.gaia_source order by source_id", dump_to_file=True)
>>>
>>> print(job)

Jobid: 1487845273526O
Phase: COMPLETED
Owner: None
Output file: async_20170223112113.vot
Results: None

>>> r = job.get_results()
>>> print(r['solution_id'])

  solution_id
-------------------
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
              ...
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
1635378410781933568
Length = 100 rows

1.5 Asynchronous job removal

To remove asynchronous

>>> from astroquery.utils.tap.core import TapPlus
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> job = gaia.remove_jobs(["job_id_1","job_id_2",...])

2. Authenticated access (TAP+ only)

Authenticated users are able to access to TAP+ capabilities (shared tables, persistent jobs, etc.) In order to authenticate a user, login or login_gui methods must be called. After a successful authentication, the user will be authenticated until logout method is called.

All previous methods (query_object, cone_search, load_table, load_tables, launch_job) explained for non authenticated users are applicable for authenticated ones.

The main differences are:

  • Asynchronous results are kept at server side for ever (until the user decides to remove one of them).
  • Users can access to shared tables.

2.1. Login/Logout

Graphic interface

Note: Tkinter module is required to use login_gui method.

>>> from astroquery.utils.tap.core import TapPlus
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> gaia.login_gui()

Command line

>>> from astroquery.utils.tap.core import TapPlus
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> gaia.login(user='userName', password='userPassword')

It is possible to use a file where the credentials are stored:

The file must containing user and password in two different lines.

>>> from astroquery.utils.tap.core import TapPlus
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> gaia.login(credentials_file='my_credentials_file')

To perform a logout

>>> from astroquery.utils.tap.core import TapPlus
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> gaia.login(credentials_file='my_credentials_file')
>>> ...
>>>
>>> gaia.logout()

2.2. Listing shared tables

>>> from astroquery.utils.tap.core import TapPlus
>>> gaia = TapPlus(url="http://gea.esac.esa.int/tap-server/tap")
>>> gaia.login(credentials_file='my_credentials_file')
>>> tables = gaia.load_tables(only_names=True, include_shared_tables=True)
>>> for table in (tables):
>>>   print(table.get_qualified_name())

public.dual
public.tycho2
public.igsl_source
tap_schema.tables
tap_schema.keys
tap_schema.columns
tap_schema.schemas
tap_schema.key_columns
gaiadr1.phot_variable_time_series_gfov
gaiadr1.ppmxl_neighbourhood
gaiadr1.gsc23_neighbourhood
...
user_schema_1.table1
user_schema_2.table1
...

3. Using TAP+ to connect other TAP services

TAP+ can be used to connect other TAP services.

Example 1: TAPVizieR.u-strasbg.fr

>>> from astroquery.utils.tap.core import TapPlus
>>> tap = TapPlus(url="http://TAPVizieR.u-strasbg.fr/TAPVizieR/tap")
>>> #Inspect tables
>>> tables = tap.load_tables()
>>> for table in (tables):
>>>   print(table.get_name())

...
J/ApJS/173/104/memb
J/A+A/376/441/table1
J/A+AS/110/81/table2
J/ApJS/73/781/snr_indx
V/15/notes
J/A+AS/115/285/refs
J/ApJS/165/338/table1
IX/24/obsnames
J/A+AS/122/463/tab2-14
J/ApJS/107/521/table1
J/MNRAS/275/1102/table1a
J/ApJ/647/328/table4
J/A+A/402/1/table1a
J/AJ/115/1856/v12
...

>>> #Launch sync job
>>> job = tap.launch_job("SELECT top 10 * from " + tables[0].get_name())
>>> r = job.get_results()
>>> r.pprint()

                       title                         class [1] ... comment
---------------------------------------------------- --------- ... -------
The 2MASS Point Source and 2MASS6x catalogues (2003)       2 ...
        The 2MASS Extended Source Catalogue (2003)         2 ...
     Astrographic catalog (mean epoch around 1900)         2 ...
AKARI IRC (9/18um) and FIS (60-160um)all-sky Surveys       2 ...
         All-Sky Compiled Catalog of 2.5M*  (2003)         2 ...
     The DENIS database (3rd Release 2005 version)         2 ...
   The Carlsberg Meridian Catalog 14 (-30<Dec<+50)         2 ...
         GALEX-DR5 sources from AIS and MIS (2011)         2 ...
       Spitzer's GLIMPSE catalogs (Galactic Plane)         2 ...
 The HST Guide Star Catalog reduced on Tycho (ACT)         2 ...
Example 2: irsa.ipac.caltech.edu
>>> from astroquery.utils.tap.core import TapPlus
>>> tap = TapPlus(url="http://irsa.ipac.caltech.edu/TAP")
>>> job = tap.launch_job_async("SELECT TOP 10 * FROM fp_psc")
>>> r = job.get_results()
>>> r.pprint()

   name      dtype   unit format n_bad
------------- ------- ----- ------ -----
       cntr   int32                  0
      hemis  object                  0
      xdate  object                  0
       scan   int32                  0
         id   int32                  0
         ra float64   deg     %r     0
        dec float64   deg     %r     0
       glon float64   deg     %r     0
       glat float64   deg     %r     0
          x float64           %r     0
          y float64           %r     0
          z float64           %r     0
    err_maj float64  arcs     %r     0
    err_min float64  arcs     %r     0
    err_ang   int32   deg            0
     x_scan float64  arcs     %r     0
     y_scan float64  arcs     %r     0
...

Please, check methods documentation to determine whether a method is TAP compatible.

Reference/API

astroquery.utils.tap Package

@author: Juan Carlos Segovia @contact: juan.carlos.segovia@sciops.esa.int

European Space Astronomy Centre (ESAC) European Space Agency (ESA)

Created on 30 jun. 2016

Classes

Tap([url, host, server_context, …]) TAP class
TapPlus([url, host, server_context, …]) TAP plus class
TapTableMeta() TAP table metadata object
TapColumn() TAP column object