<s>
Automatic	B-Application
label	I-Application
placement	I-Application
,	O
sometimes	O
called	O
text	B-Application
placement	I-Application
or	O
name	B-Application
placement	I-Application
,	O
comprises	O
the	O
computer	O
methods	O
of	O
placing	O
labels	O
automatically	O
on	O
a	O
map	O
or	O
chart	O
.	O
</s>
<s>
This	O
is	O
related	O
to	O
the	O
typographic	B-Application
design	I-Application
of	I-Application
such	I-Application
labels	I-Application
.	O
</s>
<s>
Automatic	O
text	B-Application
placement	I-Application
is	O
one	O
of	O
the	O
most	O
difficult	O
,	O
complex	O
,	O
and	O
time-consuming	O
problems	O
in	O
mapmaking	O
and	O
GIS	B-Application
(	O
Geographic	B-Application
Information	I-Application
System	I-Application
)	O
.	O
</s>
<s>
–	O
require	O
good	O
placement	O
of	O
labels	O
as	O
well	O
,	O
not	O
to	O
mention	O
engineering	O
drawings	O
,	O
and	O
professional	O
programs	O
which	O
produce	O
these	O
drawings	O
and	O
charts	O
,	O
like	O
spreadsheets	B-Application
(	O
e.g.	O
</s>
<s>
Microsoft	B-Application
Excel	I-Application
)	O
or	O
computational	O
software	O
programs	O
(	O
e.g.	O
</s>
<s>
Mathematica	B-Language
)	O
.	O
</s>
<s>
Therefore	O
,	O
a	O
GIS	B-Application
must	O
allow	O
a	O
few	O
possible	O
placements	O
of	O
each	O
label	O
,	O
and	O
often	O
also	O
an	O
option	O
of	O
resizing	O
,	O
rotating	O
,	O
or	O
even	O
removing	O
(	O
suppressing	O
)	O
the	O
label	O
.	O
</s>
<s>
Over	O
centuries	O
,	O
cartographers	O
have	O
developed	O
the	O
art	O
of	O
mapmaking	O
and	O
label	B-Application
placement	I-Application
.	O
</s>
<s>
The	O
simplest	O
greedy	B-Algorithm
algorithm	I-Algorithm
places	O
consecutive	O
labels	O
on	O
the	O
map	O
in	O
positions	O
that	O
result	O
in	O
minimal	O
overlap	O
of	O
labels	O
.	O
</s>
<s>
A	O
simple	O
algorithm	O
–	O
simulated	B-Algorithm
annealing	I-Algorithm
–	O
yields	O
good	O
results	O
with	O
relatively	O
good	O
performance	O
.	O
</s>
<s>
When	O
the	O
temperature	O
is	O
high	O
,	O
simulated	B-Algorithm
annealing	I-Algorithm
performs	O
almost	O
random	O
changes	O
to	O
the	O
label	B-Application
placement	I-Application
,	O
being	O
able	O
to	O
escape	O
a	O
local	O
optimum	O
.	O
</s>
<s>
The	O
main	O
challenges	O
in	O
developing	O
a	O
simulated	B-Algorithm
annealing	I-Algorithm
solution	O
are	O
choosing	O
a	O
good	O
evaluation	O
function	O
and	O
a	O
good	O
annealing	O
schedule	O
.	O
</s>
<s>
Another	O
class	O
of	O
direct	O
search	O
algorithms	O
are	O
the	O
various	O
evolutionary	B-Algorithm
algorithms	I-Algorithm
,	O
e.g.	O
</s>
<s>
genetic	B-Algorithm
algorithms	I-Algorithm
.	O
</s>
<s>
If	O
a	O
map	O
labeling	B-Application
problem	O
can	O
be	O
reduced	O
to	O
a	O
situation	O
in	O
which	O
each	O
remaining	O
label	O
has	O
only	O
two	O
potential	O
positions	O
in	O
which	O
it	O
can	O
be	O
placed	O
,	O
then	O
it	O
may	O
be	O
solved	O
efficiently	O
by	O
using	O
an	O
instance	O
of	O
2-satisfiability	B-Application
to	O
find	O
a	O
placement	O
avoiding	O
any	O
conflicting	O
pairs	O
of	O
placements	O
;	O
several	O
exact	O
and	O
approximate	O
label	B-Application
placement	I-Application
algorithms	O
for	O
more	O
complex	O
types	O
of	O
problems	O
are	O
based	O
on	O
this	O
principle	O
.	O
</s>
<s>
Automatic	B-Application
label	I-Application
placement	I-Application
algorithms	O
can	O
use	O
any	O
of	O
the	O
algorithms	O
for	O
finding	O
the	O
maximum	O
disjoint	O
set	O
from	O
the	O
set	O
of	O
potential	O
labels	O
.	O
</s>
<s>
Other	O
algorithms	O
can	O
also	O
be	O
used	O
,	O
like	O
various	O
graph	B-Application
solutions	O
,	O
integer	B-Algorithm
programming	I-Algorithm
etc	O
.	O
</s>
