MATERIELS AND METHODS
For each pressure type, a four-level classification (high, moderate, low, none) is
established based on the distance to the site (industries, ports, rivers, and artificial structures)
or the percentage of occupation (land use) (Table.2). For ports, the type (industrial, commercial,
leisure, fishing) is also noted. If an industrial port is within 10km, it is classified as high
pressure. An industrial port more than 10km away or a commercial port within 10km is
moderate. A commercial port more than 10km away or a leisure port within 10km is classified
as low pressure. In the absence of a port, it is none. When multiple pressures of the same type
coexist, the one closest to the station determines the classification. For coastal artificial
structures within a 10km radius, they are classified as moderate if present, none if absent.
Land use is an important parameter to assess the anthropogenic pressure in a coastal area,
it reflects the urban areas, agricultural lands, forests, and infrastructures. To assess the land use
impact, three broad categories are delineated: urban, agricultural, and natural areas. This
classification is performed by analyzing the landscape composition using two different methods
to verify the best method to assess land use:
(i) using a 10 km side grid, subdivided into 500 m x 500 m squares (Figure 5). The percentage
of land use is calculated on the basis of the number of 0.25 km
2 squares attributed to the
type of land use.
(ii) using a 10km x 10km square with the site in the center, where we considered all the area
within that square.
Satellite images with a very high spatial resolution, captured on November 19, 2018, were
obtained from Google Earth Pro. The images were projected in the WGS 1984 UTM zone 31N
coordinate system. In order to ensure the accurate representation of the spatial data, it was
necessary to apply georeferencing to these images in ArcGIS (version 10.4.1). Subsequently,
three vector layers were created in shapefile format: urban, agricultural, and natural.
The "Buffer" tool from the ArcGIS toolbox was employed to generate the 10 km x 10 km
squares situated around the stations. The identical methodology was utilized to create the 25
km squares. In order to utilize these squares on Google Earth Pro for distance measurements,
the squares in shapefile format were converted to KML format (Arctoolbox > Conversion tools
> To KML > Layer to KML). The three types of land cover (i.e., urban, agricultural, and natural)
were digitalized for land use analysis using the "Editor" tool.
For each pressure type, a four-level classification (high, moderate, low, none) is
established based on the distance to the site (industries, ports, rivers, and artificial structures)
or the percentage of occupation (land use) (Table.2). For ports, the type (industrial, commercial,
leisure, fishing) is also noted. If an industrial port is within 10km, it is classified as high
pressure. An industrial port more than 10km away or a commercial port within 10km is
moderate. A commercial port more than 10km away or a leisure port within 10km is classified
as low pressure. In the absence of a port, it is none. When multiple pressures of the same type
coexist, the one closest to the station determines the classification. For coastal artificial
structures within a 10km radius, they are classified as moderate if present, none if absent.
Land use is an important parameter to assess the anthropogenic pressure in a coastal area,
it reflects the urban areas, agricultural lands, forests, and infrastructures. To assess the land use
impact, three broad categories are delineated: urban, agricultural, and natural areas. This
classification is performed by analyzing the landscape composition using two different methods
to verify the best method to assess land use:
(i) using a 10 km side grid, subdivided into 500 m x 500 m squares (Figure 5). The percentage
of land use is calculated on the basis of the number of 0.25 km
2 squares attributed to the
type of land use.
(ii) using a 10km x 10km square with the site in the center, where we considered all the area
within that square.
Satellite images with a very high spatial resolution, captured on November 19, 2018, were
obtained from Google Earth Pro. The images were projected in the WGS 1984 UTM zone 31N
coordinate system. In order to ensure the accurate representation of the spatial data, it was
necessary to apply georeferencing to these images in ArcGIS (version 10.4.1). Subsequently,
three vector layers were created in shapefile format: urban, agricultural, and natural.
The "Buffer" tool from the ArcGIS toolbox was employed to generate the 10 km x 10 km
squares situated around the stations. The identical methodology was utilized to create the 25
km squares. In order to utilize these squares on Google Earth Pro for distance measurements,
the squares in shapefile format were converted to KML format (Arctoolbox > Conversion tools
> To KML > Layer to KML). The three types of land cover (i.e., urban, agricultural, and natural)
were digitalized for land use analysis using the "Editor" tool.