D-1 and only used
t 5 km away from
1 we evaluated the
s.
of 5 m resolution,
ate SPOT images.
y Office, Forestry
jan. To meet the
rpolated into 5 x 5
e system, TWD67
ansverse Mercator
1e central meridian
re acquired from
esearch, National
| (O SPOT Image
System calibration
> performed on the
"WD67 Transverse
m resolution to be
chose the two-date
05) because they
ds less than 10%.
d from DEM by
hade data layer by
and valleys in the
lo generate terrain
ys over the study
ophoto base maps;
the data layer by
"he data layer in a
^w data layer in a
module, and then
in position layer
> derived from the
1/2005), the other
ts stated in Hoffer
(D
ited using the four
ing algorithms are
on 3.3.3 of the free
and colleagues
nt/). And other
sion 1.0 of the free
inferences from
), and may remain
d Stohlgren, 2009).
| (he concepts of
d to describe the
ns, and Bayesian
istribution of each
pixel when the entropy reach the maximum that the state would
be extremely close to uniform distribution. That is,
MAXENT would find out the type of probability distribution
that is most likely occurring in the general state. The formula
for MAXENT is shown in following equation (2):
P. f (x)-min : : ;
= A *- — linearPredictorNormalizer | /Z
Kum 2 " max, — min, If (2)
x)-mi :
where Aoi mig 1 = hinge feature
max-min
À, = weight coefficient
linear predictor normalize = a constant for numerical
stability
Z: a scaling constant that ensures that P sums to 1
over all grid cells
2) DOMAIN derives a point-to-point similarity metric to assign
a classification value to a potential site based on its proximity
in environmental space to the most similar occurrence. The
Gower metric (Gower, 1971) provides a suitable means of
quantifying similarity between two sites. The distance of d
between two points A and B in a Euclidean p dimensional space
is defined as equation (3):
14A, -B,|
d E. k k 3
4 a Rangek ) G)
We define the complementary similarity measure R 45:
Rjp71- dig (4)
R is constrained between 0 and 1 for points within the ranges
use in Equation 3,
We define S4, the maximum similarity between candidate point
Aand the set of known record sites Tj as equation (5):
Sy =max Ry, (5)
Jel
By evaluating S for all grid points in a target area, a matrix of
continuous varying similarity values is generated which are not
probability estimates, but degrees of classification confidence
(Carpenter er al., 1993).
3) GLM is a generalization of general linear models. General
Class of linear models are made up of three components:
random, systematic, and link function. Random component
identifies response variable E(Y) and its probability distribution.
Systematic component identifies the set of predictor variables
(M. Link function identifies a function of the mean that
Is a linear function g(u) of the predictor variables. The
formula for GLM is shown in following equation (3):
Eos sua p X, v BL, (6)
where d - constants
B - regression coefficients
X — predictor variable
By using a logit link function that transforms the scale of the
response variable, being able to relax the distribution and
constancy of variances assumptions that are commonly
required by traditional linear models (McCullagh and Nedler,
1989). Consequently, the GLM model is particularly suitable
for predicting species distributions, and has been proven to be
successful in various ecological applications (Guisan ef al.,
2002).
4) Back-propagation artificial neural network (BPANN)
consists of input, hidden, and output layers. The input layer
may contain information about individual training pixels
including percent spectral reflectance in various bands and
ancillary data such as elevation, slope, etc.
Each layer consists of nodes that are interconnected. This
interconnectedness allows information to flow in multiple
directions as the network is trained. The weight of these
interconnections is eventually learned by the neural network
and stored. These weights are used during the output layer
might represent a single thematic map land-cover class.
We set four layers (one input layer, one output layer, and two
hidden layers) that can be trained using back propagation
algorithm and particle swarm optimization (PSO) algorithm is
implement. The structure of back propagation neural network
is shown in figure 2.
input values
output values
Figure 2. The structure of back propagation
artificial neural network
3.4 Model Validation
Evaluation methods of the different samplings, we used
split-sample validation. The first one (training dataset) be
used to build model; the other one (test dataset) be used to
validate the model. For each model, predicted the response of
the remaining data, and calculated the error matrix (De'ath and
Fabricius, 2000). Some common statistical measurements
included producer's accuracy, user's accuracy, overall accuracy
and Kappa coefficient (Jensen, 2005; Lillesand et al., 2008).
4. RESULSTS AND DISCUSSION
Initially, we depicted and compared the effect of micro-terrain
feature in two watersheds as shown in table 1 and figure 3.
The Tong-Feng watershed has not only steep valley but also