<s>
An	O
object-based	B-Application
spatial	I-Application
database	I-Application
is	O
a	O
spatial	B-Algorithm
database	I-Algorithm
that	O
stores	O
the	O
location	O
as	O
objects	B-Application
.	O
</s>
<s>
The	O
object-based	O
spatial	O
model	O
treats	O
the	O
world	O
as	O
surface	O
littered	O
with	O
recognizable	O
objects	B-Application
(	O
e.g.	O
</s>
<s>
Objects	B-Application
can	O
be	O
simple	O
as	O
polygons	B-General_Concept
and	O
lines	O
,	O
or	O
be	O
more	O
complex	O
to	O
represent	O
cities	O
.	O
</s>
<s>
elevation	O
)	O
vary	O
,	O
using	O
an	O
object-based	B-Application
spatial	I-Application
database	I-Application
,	O
it	O
is	O
easier	O
to	O
store	O
additional	O
attributes	O
with	O
the	O
objects	B-Application
,	O
such	O
as	O
direction	O
,	O
speed	O
,	O
etc	O
.	O
</s>
<s>
Storing	O
attributes	O
with	O
objects	B-Application
can	O
provide	O
better	O
result	O
presentation	O
and	O
improved	O
manipulation	O
capabilities	O
in	O
a	O
more	O
efficient	O
way	O
.	O
</s>
<s>
An	O
open-source	O
software	O
program	O
that	O
adds	O
support	O
for	O
geographic	O
objects	B-Application
to	O
the	O
PostgreSQL	O
object	B-General_Concept
–	I-General_Concept
relational	I-General_Concept
database	I-General_Concept
.	O
</s>
<s>
Represents	O
a	O
framework	O
of	O
objects	B-Application
as	O
classes	O
that	O
are	O
partitioned	O
into	O
three	O
kinds	O
of	O
classes	O
:	O
simple	O
classes	O
,	O
link	O
classes	O
,	O
and	O
path	O
classes	O
.	O
</s>
<s>
Objects	B-Application
of	O
a	O
simple	O
class	O
are	O
on	O
the	O
one	O
hand	O
just	O
like	O
objects	B-Application
in	O
other	O
models	O
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
,	O
objects	B-Application
of	O
a	O
simple	O
class	O
are	O
nodes	O
of	O
the	O
database	O
graph	O
–	O
the	O
whole	O
database	O
can	O
also	O
be	O
viewed	O
as	O
a	O
single	O
graph	O
.	O
</s>
<s>
Objects	B-Application
of	O
a	O
link	O
class	O
are	O
like	O
objects	B-Application
of	O
a	O
simple	O
class	O
but	O
additionally	O
contain	O
two	O
distinguished	O
references	O
to	O
source	O
and	O
target	O
objects	B-Application
(	O
belonging	O
to	O
simple	O
classes	O
)	O
,	O
which	O
makes	O
them	O
edges	O
of	O
the	O
database	O
graph	O
.	O
</s>
<s>
Finally	O
,	O
an	O
object	O
of	O
a	O
path	O
class	O
is	O
like	O
an	O
object	O
of	O
a	O
simple	O
class	O
,	O
but	O
contains	O
additionally	O
a	O
list	O
of	O
references	O
to	O
node	O
and	O
edge	O
objects	B-Application
which	O
form	O
a	O
path	O
over	O
the	O
database	O
graph	O
.	O
</s>
<s>
Additional	O
entities	O
represent	O
the	O
primitives	O
such	O
as	O
points	O
,	O
lines	O
,	O
and	O
polygons	B-General_Concept
as	O
proposed	O
in	O
related	O
models	O
.	O
</s>
