LIGO_LW format

Peter Shawhan
February 22, 2002

The standard format for data retrieved from the LDAS database is called "LIGO lightweight" or "LIGO_LW" format. This is a particular example of an XML format, with a LIGO-specific structure and conventions for representing data. A LIGO_LW file contains ordinary ASCII characters and is human-readable in principle, though of course a large file can be hard for a human to digest.

(Aside: there actually are two parallel implementations of LIGO_LW which are not quite the same:

The LDAS LIGO_LW implementation is primarily used to contain data retrieved from (or to be inserted into) the LDAS database, although other data structures (e.g. time series) can also be represented.
Daniel Sigg adopted the LIGO_LW paradigm to store configuration information and results generated by his Diagnostic Test Tools software.

At the present time, LIGOtools only includes utilities for manipulating LDAS database table data stored using the LDAS LIGO_LW implementation.)

Here is a sample LIGO_LW file containing a table with columns and rows selected from the sngl_inspiral table: inspiral_events.xml.
Other FAQ articles describe various thing that you can do with such a file.