<s>
3D	B-Application
Structure	I-Application
Change	I-Application
Detection	I-Application
is	O
a	O
type	O
of	O
Change	B-Application
detection	I-Application
(	O
GIS	B-Application
)	O
processes	O
for	O
GIS	B-Application
(	O
geographical	B-Application
information	I-Application
systems	I-Application
)	O
.	O
</s>
<s>
A	O
high-spatial	O
resolution	O
Digital	B-Application
elevation	I-Application
model	I-Application
(	O
DEM	O
)	O
that	O
provides	O
accurate	O
4-d	O
(	O
space	O
and	O
time	O
)	O
structural	O
information	O
over	O
area	O
of	O
interest	O
is	O
required	O
to	O
compute	O
such	O
changes	O
.	O
</s>
