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the spatial influence on the opinion.
O
k
lies in the domain [0
,
1] where 0 is a
maximum negative opinion, i.e. a full rejection of a location and 1 a maximum
positive opinion.
The initial opinions of the agents purely results from individual decision-
making based on the desires of an agent [21]. It is the result of a process where
an agent evaluates the spatial and non-spatial aspects which it considers im-
portant for realizing its desires. It takes into account solely the agents current
knowledge about the environment. In the ABM this internal decision-making
is done following a classical rule based approach. Each agent has a number of
desires, which are then translated to a number of rules. Executing these rules
lead to a set of location specific opinions.
The social influence describes the effect of other agents in the social network.
The social influence changes the opinion of an agent about, in this case, the
suitability of a location for a specific land use function. This process of social
influence (sometimes referred to as contagion) is well described in sociology.
Social influence occurs through processes of communication or comparison [22].
The strength of the influence depends on the structure of the social network
and especially on the number, length and strength of the links between actors
[17, 22]. In spatial planning systems, social networks often show a high clustering
of individual actors strongly connected based on similar interests of living in
the same location. Examples of such clusters are environmental interest groups,
neighborhood or farmers communities. As a key measure of social influence the
concept of social-distance as found in the DW and HK models is adopted here.
Social distance is defined as the difference between two agent for their opinions
for a specific location:
S
(
k,l,i,j,t
)
=
o
(
k,i,j,t
)
−
o
(
l,i,j,t
)
(5)
Where:
S
(
k,l,i,j
)
is the social distance between agents
k
and
l
for location
i,j
at
time
t
and
o
(
k,i,j,t
)
is the opinion of agent
k
and
o
l,i,j,t
the opion of agent
l
about
location
i,j
.
Social influence is defined as the ratio between the number of agents having
an opinion within a certain treshold and the total number of agents having an
opinion about that location:
Qsoc
(
k,g,i,j,t
)
=
l
=1
w
(
l,g,i,j,t
)
N
(6)
Where
Qsoc
(
k,g,i,j,t
)
is the social influence factor for agent
k
for land use
g
at
location
i,j
for time
t
,
N
is the total number of agents and
w
(
l,g,i,j,t
)
is the dirac
delta function for agent
l
:
w
(
l,g,i,j,t
)
1if
S
(
k,l,i,j,t
)
<d
(
k,g,i,j,t
)
(7)
0otherwise
Where
d
(
k,i,j,g
)
is a threshold value for agent
k
for entering a negotiation.
The spatial influence, which is specific for land use systems, deals with the
distribution of opinions in a geographic space. The assumption made here is
