johannes-sahlmann / pygacs

Toolkit to manipulate Gaia catalogue tables hosted at ESAC archive.

pygacs

Python toolkit to manipulate Gaia catalogue tables hosted at ESA's Gaia Archive Core Systems (GACS)

pygacs provides python modules for the access and manipulation of tables in GACS, e.g. basic query on a single table or crossmatch between two tables. It employs the TAP command line access tools described in the 'Help' section of the GACS web pages (http://archives.esac.esa.int/gaia/).

Both public and authenticated access have been implemented.

Please see pygacsExample_publicAccess.py for a demo on how public tables can easily be queried using ADQL.

To fully use pygacs, in particular to upload a table for crossmatch operations, you will need to be a registered user of GACS and call the example script pygacsExample.py with your access credentials.

Basic example usage

# import module

import pygacs.public.publicAccessTools as pgp

# define ADQL query

queryString = '''SELECT * FROM gaiadr1.tgas_source WHERE parallax > 100; '''

# define local file to store query result in a VO table

outputFileName = path + 'ADQL_query_result.vot';

# execute query

pgp.retrieveQueryResult(queryString,outputFileName);

# read result into astropy table

T = Table.read(outputFileName,format='votable')

Documentation

All classes and methods/functions include basic documentation.

Installation notes

This package was developed in a python 2.7 environment, but was also successfully tested using python 3.5.

The following python packages are required:

• numpy
• astropy
• xmltodict

Optional (for plotting in the example script):

• matplotlib
• pylab

How to run the example script

You may use pip for installation:

> pip install pygacs

Or get the source files, e.g.:

> git clone https://github.com/johannes-sahlmann/pygacs

Install pygacs:

> cd pygacs

> python setup.py install --user

To run the example script, do:

> cd examples/

For public access:

> ./pygacsExample_publicAccess.py

For authenticated access:

> ./pygacsExample.py --help

> ./pygacsExample.py yourGacsUserName yourGacsPassword

Attribution

Please acknowledge the ESA Science Archives Team and the Gaia Data Processing and Analysis Consortium (DPAC) if you used this code in your research.

License

Copyright (c) 2015-2016 Johannes Sahlmann, Gaia Data Processing and Analysis Consortium

pygacs is open source and free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.