Geography Reference
In-Depth Information
S
v,u,p,t+1
is larger than 1, the vth type of vegetation is more superior than the uth
type of vegetation in the pixel p in the (t + 1)th year. A more exact mathematical
formula for judging the dominance relations of multiple types of vegetation is
proposed in the agent-based module.
2.1.1.4 Agent-based Module
Determination of land use change is partly characterized by non-rationality such as
tradition and custom. The agent-based module identifies if the land use change
demand simulated by economic module and the possible vegetation change assessed
by vegetation change module can be realized under the background of irrational
decisions. Agent-based modeling is able to simulate land use change by measuring
the individual behavior and results of land use over time. Take the decision of land
use change of a given household for instance. The dissimilarities between a given
household h and all defined household groups in the population can be measured.
"
#
2
D
h
;
g
¼
X
V
h
;
s
V
g
;
s
S
w
s
ð
2
:
9
Þ
V
h
;
s
þ
V
g
;
s
s¼1
where, D
h,g
is the distance from household h (h = 1, 2, …,H) to the household
group g (g = 1, 2, …,G). V
h,s
is the value of variable s (s = 1, 2, …,S) repre-
senting the character of household h. V
g
;
s
is the average value of variable s of
households in household group g; w
s
is the weight coefficient of the variable s in
explaining the character of household and household group.
The household h is assigned into the most similar household group and makes
the same land use change decision with the household group.
g
0
¼ arg
min D
h
;
1
;
D
h
;
2
; ;
D
h
;
g
; ;
D
h
;
G
ð
2
:
10
Þ
where, g
0
is the most similar household group to household h. By establishing a
case database of land use change decision, we can assign each household into one
similar enough household group and deduce the land use decision. It helps correct
the land use change results simulated of economic module based on ideas of
optimization.
For the assessment result of vegetation change module, the agent-based module
also provides a criterion to judge which kind of vegetation change will happen in a
specific pixel.
<
:
if for
8
u
6
¼ v
;
P
v
;
p
;
t
þ
1
[ 0 and S
v
;
u
;
p
;
t
þ
1
[ 1 or
0
;
or P
v
;
p
;
t
þ
1
0 and S
v
;
u
;
p
;
t
þ
1
[ 0 or
1;
1
;
L
v
;
p
¼
ð
2
:
11
Þ
if for
8
u
6
¼ v
;
P
v
;
p
;
t
þ
1
[ 0 and S
v
;
u
;
p
;
t
þ
1
[ 0 or
1
;
or P
v
;
p
;
t
þ
1
0 and S
v
;
u
;
p
;
t
þ
1
[ 1 or
0
:
0
;
