<s>
Vega	O
and	O
Vega-Lite	O
are	O
visualization	O
tools	O
implementing	O
a	O
grammar	O
of	O
graphics	O
,	O
similar	O
to	O
ggplot2	B-Application
.	O
</s>
<s>
Vega	O
is	O
used	O
in	O
the	O
back	O
end	O
of	O
several	O
data	B-Application
visualization	I-Application
systems	O
,	O
for	O
example	O
Voyager	O
.	O
</s>
<s>
Chart	O
specifications	O
are	O
written	O
in	O
JSON	B-General_Concept
and	O
rendered	O
in	O
a	O
browser	O
or	O
exported	O
to	O
either	O
vector	O
or	O
bitmap	O
images	O
.	O
</s>
