<s>
TOPCAT	B-Application
is	O
an	O
interactive	O
graphical	O
viewer	O
and	O
editor	O
for	O
tabular	O
data	O
.	O
</s>
<s>
Although	O
a	O
general	O
purpose	O
tool	O
capable	O
of	O
handling	O
large	O
and	O
sparse	O
datasets	B-General_Concept
with	O
correlation	O
functionality	O
its	O
specialist	O
application	O
area	O
is	O
astronomy	O
and	O
it	O
was	O
initially	O
designed	O
to	O
support	O
virtual	B-Application
observatories	I-Application
.	O
</s>
<s>
The	O
Acronym	O
TOPCAT	B-Application
derives	O
from	O
Tool	O
for	O
OPerations	O
on	O
Catalogues	O
And	O
Tables	O
.	O
</s>
<s>
Initially	O
funded	O
from	O
the	O
Starlink	B-Operating_System
Project	I-Operating_System
it	O
has	O
been	O
funded	O
by	O
various	O
other	O
projects	O
since	O
.	O
</s>
<s>
Written	O
in	O
Java	B-Language
,	O
TOPCAT	B-Application
can	O
be	O
used	O
both	O
standalone	O
and	O
within	O
a	O
web	O
browser	O
.	O
</s>
<s>
Muna	O
,	O
in	O
his	O
2016	O
paper	O
"	O
Introducing	O
Nightlight	O
:	O
A	O
New	O
FITS	O
Viewer	O
"	O
,	O
observes	O
that	O
,	O
TOPCAT	B-Application
and	O
are	O
the	O
most	O
common	O
tools	O
used	O
to	O
view	O
FITS	O
files	O
.	O
</s>
<s>
VisIVO	O
is	O
an	O
alternative	O
tool	O
for	O
working	O
with	O
virtual	B-Application
observatories	I-Application
.	O
</s>
<s>
While	O
TOPCAT	B-Application
is	O
unable	O
to	O
visualise	O
catalogues	O
as	O
a	O
set	O
of	O
vectors	O
it	O
does	O
have	O
capabilities	O
to	O
explore	O
correlations	O
in	O
two	O
and	O
three	O
dimensional	O
scatter	O
plots	O
.	O
</s>
<s>
The	O
STILTS	O
application	O
complements	O
TOPCAT	B-Application
with	O
similar	O
capabilities	O
but	O
is	O
considered	O
a	O
steeper	O
learning	O
curve	O
,	O
however	O
STILTS	O
does	O
have	O
the	O
advantage	O
of	O
being	O
able	O
to	O
be	O
scripted	O
.	O
</s>
<s>
TOPCAT	B-Application
is	O
used	O
in	O
training	O
for	O
use	O
of	O
virtual	B-Application
observatories	I-Application
,	O
including	O
access	O
via	O
the	O
Astronomical	B-Language
Data	I-Language
Query	I-Language
Language	I-Language
(	O
ADQL	B-Language
)	O
.	O
</s>
<s>
Applications	O
using	O
TOPCAT	B-Application
include	O
MultiDark	O
,	O
a	O
database	O
for	O
results	O
from	O
cosmological	O
simulations	O
.	O
</s>
