STIL

Starlink Tables Infrastructure Library

Generic Java Table Handling for Astronomy

• What is STIL?
• Features
• Generic
• VOTable
• Experimental (includes new command-line tool tpipe)
• Supported Formats
• Documentation
• Downloads
• Further Information

What is STIL?

STIL is a pure Java library for generic input, output and processing of tabular data. It presents to the application programmer a view of a table which looks the same regardless of whether it came from a FITS file, a VOTable, an ASCII text file, a query on a relational database, or whatever. Thus the application doesn't have to worry about the storage format of tables either when reading or writing them, it can concentrate on doing processing. STIL's idea of a table is rich enough to include table and column metadata, and table cells which contain scalar or single- or multi-dimensional array data of numerical, string or other types. This is well suited to astronomical data, though it can be of use in other fields as well.

STIL comes with a large range of supported input and output formats (including VOTable, FITS, SQL, ASCII, CSV) and can be extended to cope with still others.

Features

Generic Features

The generic table I/O has the following features:

• Many table serialization formats supported
• Pluggable architecture allows addition of new formats
• Any-to-any format conversion is trivial
• Access to large tables is possible (not constrained by memory)
• Full javadocs and programmer's tutorial/overview documentation
• GUI components provided including full table drag and drop support

VOTable Features

STIL includes sophisticated facilities for VOTable I/O which can, if desired, be used largely independently of the rest of the package. As well as the general features listed above this has the following features:

• Reads and writes all VOTable data formats (TABLEDATA, FITS, BINARY) - believed to be the only library which does this
• Full DOM access to hierarchical document structure, without heavy memory use
• Hybrid SAX/DOM parsing for efficient input
• Flexible table output (you can construct hierarchical documents)
• Parsing does not attempt network connections to retrieve VOTable DTD/schema
• Best-efforts parsing of non-conforming/invalid documents
• Full compatibility with VOTable 1.0 and 1.1 standards
• Full ID/ref crossreferencing

Experimental and Future Features

STIL development is ongoing. The following features are present in the library but not fully documented and subject to major changes:

Command-line tools

The tablecopy tool is provided for simple table format conversion.
New at release 2.2 is a general purpose command-line table processing pipeline called tpipe which can do row selection, sorting, column rearrangement, algebraic manipulations, and many other things. More command-line tools, including a table-matching one, are planned but not yet present.

Table matching

Classes in the uk.ac.starlink.table.join package provide efficient facilities for table joins based on exact or fuzzy coordinate matches, suitable for medium-sized tables (<= 10⁶ rows or so). These are not well documented, but work, and are used in TOPCAT.

Other features, such as more I/O handlers and better handling for errors and astronomical co-ordinates, are planned but not yet included.

If you have requests, or would like to see specific features in STIL sooner rather than later, please get in touch and I may be able to oblige.

Supported Formats

The following formats are currently supported for table input:

• FITS
• VOTable
• SQL
• ASCII
• Comma-Separated Value
• World Data Center

• FITS
• VOTable
• SQL
• ASCII
• Comma-Separated Value
• Human-readable text
• HTML
• LaTeX
• Mirage

Documentation

There are two main sources of documentation for STIL:

• The main programmer's overview document is SUN/252, available as:
• Multi-page HTML document
• Single HTML document
• PDF file
• XML source
• The definitive API documentation is available in the javadocs:
• Browse javadocs online

You can download the full documentation set (SUN/252 in various forms plus javadocs) in the documentation zip file.

Downloads

The current version of STIL is 2.2 , released February 2005.

STIL is released under the GPL. The main components are available here:

• Standalone jar file (1.2M) - compiled classes
• Documentation zip file - HTML/PDF user document and javadocs
• Source code zip file (0.5M)

There are alternative ways of obtaining the compiled classes:

• Download TOPCAT (all the STIL libraries are contained in the TOPCAT installation)
• Download the entire Starlink java set, of which STIL forms part
• Get the Starlink CD (ISO image) containing all Starlink software - but note it may not contain the most recent version of STIL

Note that while the source code archive above contains all the original code in STIL, it may not suffice to build it. If you need build files etc, contact me.

Previous versions can be found at ftp://andromeda.star.bris.ac.uk/pub/star/stil/. You can see the version history in the user document.

STIL has been developed using the Java 2 Standard Edition 1.4.1, but is expected to work with any 1.4 or 1.5/5.0 version of the J2SE.

Further Information

If you like STIL, you'll love TOPCAT, a graphical tool for table browsing / plotting / analysis / editing which benefits from all STIL's features.

If you have any comments, questions, requests, bugs etc, please contact me:

• Author: Mark Taylor, Astrophysics group, Physics Department, Bristol University
• Email: m.b.taylor@bristol.ac.uk
• STIL WWW page: http://www.starlink.ac.uk/stil/
• Starlink: http://www.starlink.ac.uk/