TOPCAT is an interactive graphical viewer and editor for tabular data. Although a general purpose tool capable of handling large and sparse

dataset A data set (or dataset) is a collection of data. In the case of tabular data, a data set corresponds to one or more database tables, where every column of a table represents a particular variable, and each row corresponds to a given record o ...

s with

correlation In statistics, correlation or dependence is any statistical relationship, whether causal or not, between two random variables or bivariate data. Although in the broadest sense, "correlation" may indicate any type of association, in statistics ...

functionality its specialist application area is

astronomy Astronomy is a natural science that studies celestial objects and the phenomena that occur in the cosmos. It uses mathematics, physics, and chemistry in order to explain their origin and their overall evolution. Objects of interest includ ...

and it was initially designed to support

virtual observatories Virtual may refer to: * Virtual image, an apparent image of an object (as opposed to a real object), in the study of optics * Virtual (horse), a thoroughbred racehorse * Virtual channel, a channel designation which differs from that of the actual ...

. It is able to handle several digital file formats including

FITS Flexible Image Transport System (FITS) is an open standard defining a digital file format used for storage, transmission and processing of data: formatted as multi-dimensional arrays (for example a 2D image), or tables. FITS is the most commonl ...

which is in common use in astronomy. The Acronym ''TOPCAT'' derives from ''Tool for OPerations on Catalogues And Tables''.

History

The project was initially developed by Mark Taylor, an astrophysicist from the

University of Bristol The University of Bristol is a public university, public research university in Bristol, England. It received its royal charter in 1909, although it can trace its roots to a Merchant Venturers' school founded in 1595 and University College, Br ...

in 2003. Taylor acknowledges inspiration for some features from ''Mirage'' from

Bell Labs Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, Murray Hill, New Jersey, the compa ...

and ''VOPlot'' from VO-India. Initially funded from the

Starlink Project The Starlink Project, referred to by users as ''Starlink'' and by developers as simply ''The Project'', was a UK astronomical computing project which supplied general-purpose data reduction software. Until the late 1990s, it also supplied comput ...

it has been funded by various other projects since.

Features

Written in

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

, TOPCAT can be used both standalone and within a web browser. It is suitable for use as a graphical viewer and data editor of tabular data from FITS and other sources. Muna, in his 2016 paper "Introducing Nightlight: A New FITS Viewer", observes tha
SAOImage DS9
TOPCAT an
Fv
are the most common tools used to view FITS files. VisIVO is an alternative tool for working with virtual observatories. While TOPCAT is unable to visualise catalogues as a set of vectors it does have capabilities to explore correlations in two and three dimensional scatter plots.

STILTS

The STILTS application complements TOPCAT with similar capabilities but is considered a steeper learning curve, however STILTS does have the advantage of being able to be scripted.

Applications

TOPCAT is used in training for use of

, including access via the Astronomical Data Query Language (ADQL). Applications using TOPCAT include MultiDark, a database for results from

cosmological Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe, the cosmos. The term ''cosmology'' was first used in English in 1656 in Thomas Blount's ''Glossographia'', with the meaning of "a speaking of the wo ...

simulations.

References

Sources

* * * * * * * * * * *

External links

* * {{Portal bar, Free and open-source software Free plotting software