TOPCAT TOPCAT
-disk flag less often required for large tables.
What is TOPCAT?TOPCAT is an interactive graphical viewer and editor for tabular data. Its aim is to provide most of the facilities that astronomers need for analysis and manipulation of source catalogues and other tables, though it can be used for non-astronomical data as well. It understands a number of different astronomically important formats (including FITS and VOTable) and more formats can be added.
It offers a variety of ways to view and analyse tables, including a browser for the cell data themselves, viewers for information about table and column metadata, and facilities for 1-, 2-, 3- and higher-dimensional visualisation, calculating statistics and joining tables using flexible matching algorithms. Using a powerful and extensible Java-based expression language new columns can be defined and row subsets selected for separate analysis. Table data and metadata can be edited and the resulting modified table can be written out in a wide range of output formats.
It is a stand-alone application which works quite happily with no network connection. However, because it uses Virtual Observatory (VO) standards, it can cooperate smoothly with other tools in the VO world and beyond, such as VODesktop, Aladin and ds9. Between 2006 and 2009 TOPCAT was developed within the AstroGrid project, and is offered as part of a standard suite of applications on the AstroGrid web site, where you can find information on several other VO tools.
The program is written in pure Java and available under the GNU General Public Licence. It was initially developed within the now-terminated Starlink project in the UK, and was more recently developed and supported by its author as part of the AstroGrid project. Its underlying table processing facilities are provided by STIL.
FeaturesThe following is a list of the program's main capabilities. The hyperlinks are to the relevant parts of the user document.
Supported table input formats include:
tabular environment DocumentationFull tutorial and reference documentation for TOPCAT is provided by SUN/253, the user document. This is available within the program at runtime via the context-sensitive help system, or in the following forms within the distribution or on the web:
Frequently Asked QuestionsA list of frequently asked questions is available. If you want to suggest additional questions and/or answers, please get in touch.
ScreenshotsYou can see screenshots of TOPCAT in action in the following places:
Obtaining TOPCATTOPCAT is written in the Java language using the Java 2 Standard Edition version 1.4 and should run on any J2SE 1.4, 1.5 or 1.6 system. This means it can be run on a wide range of platforms, without requiring any recompilation - you just need to ensure that you have a suitable Java Runtime Environment (JRE). If you don't have Java installed, or have an unsuitable version, you can obtain it for Linux, Solaris and MS Windows from Sun's web site (you only need the "JRE" rather than the "SDK" download, unless you will be doing development work). J2SE Runtime Enviroments (sometimes called JVM or Java Virtual Machines) for other platforms may be available from operating system vendors; in particular TOPCAT is known to run (though not currently exhaustively tested) on MacOS X (see here).
Note Various open-source java implementations
(GNU's gij, OpenJDK-based implementations) tend not to
work well at time of writing - these are sometimes bundled
with Linux distributions.
If you have one of these (try java -version to find out),
you are advised to get the Sun implementation instead.
Having got Java, There are several ways to download TOPCAT, described in rough order of advisability in the following subsections. More information on how to run the program having obtained it can be found in SUN/253's section on Invoking TOPCAT.
The most convenient form for downloading is to pick up a single Jar file containing the required classes:
On Unix-like operating systems, download one or other of these
jar files and the startup script topcat
into the same directory chmod +x topcat,
and you can just run the command:
topcatOn non-Unix systems the script won't work, and you can use a command like:
java -jar topcat-*.jaror invoke it in some other system-dependent way such as by clicking on it.
For many users, topcat-lite will provide all the features
they need. The optional extras provided by topcat-full include:
topcat-full lacks a few of the niche features
(SPLAT spectrum viewer, proper coordinate handling in SoG),
since these require native libraries; for these you will need the
Full Starjava installation described below.
WebStart is a Java technology which enables one-click download, installation, updating and invocation of Java applications over the web. If you have Java's WebStart installed, you can install and invoke TOPCAT in one click from one of the following links:
topcat-lite and topcat-full.
If you want the most comprehensive installation then download and unpack the full starjava tree in one of the following forms:
starjava/bin/topcat script
(Unix) or by running java -jar starjava/lib/topcat/topcat.jar.
If you have a Macintosh, you can pick up the following for easy installation:
topcat-full.dmg (19.7M)
Version HistoryThe most recent public release of TOPCAT is version 3.5, released 6 November 2009.
For a detailed history of the changes in this and previous releases, see the
Full Version Historysection of SUN/253.
Further Information
svn checkout https://starjava.jach.hawaii.edu/svn/trunk
(see FAQ)TOPCAT is currently (2009) under active, though intermittent, development, and I'm very open to user feedback. Any comments, questions, requests, bugs, job offers etc, please contact me: