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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004
functions. Each processing method has one or some outputs
that depends on processing method type, entering raw data
structure (Vector or Raster) and requiring data for entering
analytical functions. There are different kinds of processing
methods in GIS environment (for example: data combination,
vector to raster conversion, distance map production,
reclassification, etc).
2.3 Integration Models
Various models were used for real world events simulation in
GIS environment (Aronof, 1989). Integration model is one of
them that used for site selection by integrating related spatial
data and effective criteria. There are various integration models
that categorized by kind of functions and their executive routine
(Knowledge driven or Data driven). -
Knowledge driven: Experts experience and scientists science
are used for executing models.
Data driven: Models are executed based on existent solutions
and dependency value computation.
We'll describe some useful models that have been used in our
application and mention our reasons for selecting them. These
models consist of: Boolean Operation, Indexing Overlay, Fuzzy
Logic and Genetic Algorithm.
2.3.1 Boolean Operation : In this model, input maps are
integrated by using logical operators such as AND, OR, XOR
and NOT (Bonham Carter and G.F., 1991). Although, Boolean
Operation is an easy and fast model to run, there are some
problems in its execution routine. In this model, all input factor
maps (processed data) have same weights and appropriate sites
can’t be separated based on their priority. In our research for
industrial estate site selection, this model isn't used because of
mentioned problems and weighted nature of efficient criteria
and conditions in our application.
2.3.2 Index Overlay Model: Factor maps are integrated
using following Equation :
5S.
code NE. (1)
>; Wi
where Wi- The weight of ith factor map
Si- The ith spatial class weight of jth factor map
S= The spatial unit value in output map
Comparing Index Overlay with Boolean Models executive
routines, it is identified that Index Overlay model has more
flexibility and ability for priority indication on spatial units of
factor maps (Bonham Carter and G.F., 1991). With respect to
mentioned characteristics, this model is useful for comparing
and evaluating integration models in industrial estate site
selection process.
2.3.3 Fuzzy Logic Model: In industrial estate site selection
application, for each factor map we can define classes and
spatial units as a subset that their membership values in
industrial estates convenient location are mapped between 0 and
1. There are some fuzzy operators such as Fuzzy AND, Fuzzy
OR, Fuzzy Product, Fuzzy Sum and Fuzzy y that are used for
factor maps integration (An and Moon, 1991).
Fuzzy AND : This operator operates like common statements
in classic sets theory as Equation 2.
H combination = MIN (u P Hu T Hh y) (2)
where
Keombination= Each spatial unit value in output map
HA Rc..- Spatial units membership values
This is used when there have been two or more factors or
evidences together that can help solving the problem. In our
application, this operation isn't used because of its weakness on
participating all effective factors and lack of specific evidences
for industrial estates location.
Fuzzy OR : This operator operates like union statements in
classic sets theory as Equation 3.
M Combinatia = MAX ME) (3)
where combination“ Each unit value in output map
Ua pc... = Spatial units membership values
This operator is used when there are sufficient positive factors
and evidences in study area. In our evaluation, because of lack
of positive factors for industrial estates site selection, Fuzzy OR
operator isn't used.
Fuzzy Product : Fuzzy Product Operator produces input factor
maps membership values and emplaces results on output map
(Equation 4). Therefore, it has decreasing affects on results and
is used when input factor maps debilitate each other.
n
HV. Combination ES ; [1 ju (4)
lI = i
where combination” Each unit value in output map
u;- The weight of ith factor map
In industrial estates site selection, There is not weakener factor
maps then fuzzy product isn't used in our evaluation.
Fuzzy Sum : This operator is defined as following Equation.
n
H combination = b C Holl H, )) (5)
i=]
Where combination“ Each unit value in output map
Wi= The weight of ith factor map
This operator is used when input factor maps have increasing
effects in each other. In our application, because of increasing
effects of Accessing factors and Infrastructure parameters, this
operator was used and compared with other integration
operators.
Fuzzy y : This operator is a general form of Fuzzy Product and
Sum operators (Equation 6).
ö -à
M combination = (Fuzzy Sum) % (FuzzyProduet) (6)
According to Equation 6, y can change from 0 to 1. This
operator is used when there have been increasing and
decreasing effects on interactions of evidences
(Zimmermannand and Zayo, 1980). This operator is used for