MATERIELS AND METHODS
In the first method (§ 2.2.1.i) a 10 km side grid was applied to the image, subdivided into
500 m x 500 m squares, using the "Create Fishnet" tool from Arctoolbox. This was done by
overlaying it directly on the digitalized area within the 10 km squares. In the second method (§
2.2.1.ii), all the area within this square was considered. The predominant land use type is
evaluated in each 0.25 km
2 square along the coastline. The number of squares attributed to the
type of land use were then calculated. The percentage of occupation type is determined by the
number of squares allocated to each type (urban, agricultural and natural). The percentage of
the different types of land use is used to classify this type of pressure: high, moderate, low or
no pressure (Figure 8).
The five elements presented in Table 2 are used to assess the total pressure exerted on
each of the stations. These different factors allow estimating the overall human pressures that
apply to the areas surrounding the study stations.
Then we have considered all the pressure classes assigned to each site in order to
characterize each one of them as having high, moderate, low or none pressure (Table3).
For a later correlation with the ground truth data, we need to convert the type of pressure
into a numerical value, the value of 3 is attributed for high pressure, 2 for moderate, 1 for low,
and 0 for none, (Table 4). Then we calculated a quotation for each site by considering the
average of the scores obtained for each of the pressures. Finaly, we adopted the approach
suggested by Garcia Marin (2013) to interpret each quotation.
Table 2. Classification of the 5 types of pressure considered (land use, river, industry,
ports and artificial structure) (Lopez Y Royo et al. 2009).
Type of pressure
High (3)
Moderate (2)
Low (1)
None (0)
Land use
(% coastline)
Urban: >90%
Natural: <50%;
Urban +agricultural: >50%
Urban + agricultural: 50%;
or only agricultural: <90%
Natural:
>90%
River (distance
from site)
n/a
<10Km
(in the same bay)
>10 km
None
Industry (distance
from site)
<10Km
Industry: >10 km
n/a
None
Ports (type and
distance from site)
Industrial: <10
km
Industrial: >10 km and/or
commercial: <10 km
Commercial: >10 km;
recreational: <10 km
None
Artificial structures
n/a
Yes
n/a
None
n/a: no answer.
In the first method (§ 2.2.1.i) a 10 km side grid was applied to the image, subdivided into
500 m x 500 m squares, using the "Create Fishnet" tool from Arctoolbox. This was done by
overlaying it directly on the digitalized area within the 10 km squares. In the second method (§
2.2.1.ii), all the area within this square was considered. The predominant land use type is
evaluated in each 0.25 km
2 square along the coastline. The number of squares attributed to the
type of land use were then calculated. The percentage of occupation type is determined by the
number of squares allocated to each type (urban, agricultural and natural). The percentage of
the different types of land use is used to classify this type of pressure: high, moderate, low or
no pressure (Figure 8).
The five elements presented in Table 2 are used to assess the total pressure exerted on
each of the stations. These different factors allow estimating the overall human pressures that
apply to the areas surrounding the study stations.
Then we have considered all the pressure classes assigned to each site in order to
characterize each one of them as having high, moderate, low or none pressure (Table3).
For a later correlation with the ground truth data, we need to convert the type of pressure
into a numerical value, the value of 3 is attributed for high pressure, 2 for moderate, 1 for low,
and 0 for none, (Table 4). Then we calculated a quotation for each site by considering the
average of the scores obtained for each of the pressures. Finaly, we adopted the approach
suggested by Garcia Marin (2013) to interpret each quotation.
Table 2. Classification of the 5 types of pressure considered (land use, river, industry,
ports and artificial structure) (Lopez Y Royo et al. 2009).
Type of pressure
High (3)
Moderate (2)
Low (1)
None (0)
Land use
(% coastline)
Urban: >90%
Natural: <50%;
Urban +agricultural: >50%
Urban + agricultural: 50%;
or only agricultural: <90%
Natural:
>90%
River (distance
from site)
n/a
<10Km
(in the same bay)
>10 km
None
Industry (distance
from site)
<10Km
Industry: >10 km
n/a
None
Ports (type and
distance from site)
Industrial: <10
km
Industrial: >10 km and/or
commercial: <10 km
Commercial: >10 km;
recreational: <10 km
None
Artificial structures
n/a
Yes
n/a
None
n/a: no answer.