The Application of GIS and Remote Sensing in a Spatiotemporal Analysis...
57
proved that at least 66% of the sandy coastal strip of the Gulf of Mexico is set back [9]
and 45% of beaches from Florida to North Carolina [10] as well as 40% of Califor‑
nian beaches [11: pp. 13–14]. Based on a long‑term morphodynamic and stratigra‑
phy analysis of coastal barriers, annual shoreline mapping using the Differential
Global Positioning System (DGPS) and local beach profile measurements, Dillen‑
burg et al. [12], respectively estimated that 81–84% of the beaches of the State of
Rio Grande do Sul (Brazil) would be eroded. In Asia, Gopinath and Seralathan [13]
showed by comparing Landsat imageries of 1996, 1998, 1999 to a topographic map
of 1967 that in the Bay of Bengal, erosion has affected 29.8 km
2
of the Sagar Island
between 1967 and 1999. El-Hattab [14], assessed the vulnerability of the Northern
Mediterranean coast of the Nile Delta using Landsat imageries and an improved
Coastal Vulnerability Index incorporation 10 variables (geology, geomorphology,
topography, slope, erosion/accretion, mean sea level rise, and coastal protection,
population density and socioeconomic status...) and revealed that over 29.64% of the
considered coastline is at a very high risk. Recently, Torresan et al. [15] assessed
the vulnerability of the Mediterranean coasts of Egypt using a climate improved
coastal vulnerability index that proposed a new approach incorporating geologi‑
cal and socioeconomic parameters in addition to physical ones. This showed that
approximately 43 km² (1%) of the coastal area is at high and very high risk while
over 80% (4652 km²) has been classified at low vulnerability. In East Africa, an as‑
sessment of the evolution of the Kudichi coastline (Dar es Salam/Tanzania) through
superposition and analysis of aerial photographs of 1981, 1992 and 2002 showed
that between 1981 and 2002, 0.61 ha of land was eroded in the Kudichi area, with
an important accretion of about 2.21 ha, a loss 0.40 ha of mangrove area has been
also recorded [16]. In West Africa, Ozer et al. [17] used high resolution Google Earth
images to evaluate trends of coastline changes in Benin and Togo from 2000 to 2015
and revealed that 52% of the coastline is undergoing erosion processes while some
sections experience an accumulation (14%).
In Senegal, coastline retreat analysis involved 2 major approaches over time.
The first one was mostly oriented towards the interpretation of ancient geologi‑
cal map with reference to the sea level (marine transgression and regression). The
second approach dealt with the analysis of contemporary geospatial tools involv‑
ing aerial photographs, cadastral maps and recently satellite images. In the par‑
ticular area of Rufisque, coastline change studies were essentially based on the
analysis of iconographic documents (aerial photographs, topographic maps, ca‑
dastral maps, nautical charts, high resolution satellite images). Diallo [18], detect‑
ed a shoreline evolution rate of −1.29 m/year in Rufisque using topographic maps
(1933, 1948), cadastral map (1987), and non-rectified aerial photographs (1980).
In the same area, a coastline erosion of 1.3 m/year has been recorded by Sall [19]
by analyzing cadastral maps (1933, 1945) and a non-rectified aerial photograph
of 1980 while Niang -Diop [20] used non-rectified aerial photographs of (1959,
1968, 1972, 1976, 1980) to come up with −1.2 m of annual coastal change. Dieye [21]
57
proved that at least 66% of the sandy coastal strip of the Gulf of Mexico is set back [9]
and 45% of beaches from Florida to North Carolina [10] as well as 40% of Califor‑
nian beaches [11: pp. 13–14]. Based on a long‑term morphodynamic and stratigra‑
phy analysis of coastal barriers, annual shoreline mapping using the Differential
Global Positioning System (DGPS) and local beach profile measurements, Dillen‑
burg et al. [12], respectively estimated that 81–84% of the beaches of the State of
Rio Grande do Sul (Brazil) would be eroded. In Asia, Gopinath and Seralathan [13]
showed by comparing Landsat imageries of 1996, 1998, 1999 to a topographic map
of 1967 that in the Bay of Bengal, erosion has affected 29.8 km
2
of the Sagar Island
between 1967 and 1999. El-Hattab [14], assessed the vulnerability of the Northern
Mediterranean coast of the Nile Delta using Landsat imageries and an improved
Coastal Vulnerability Index incorporation 10 variables (geology, geomorphology,
topography, slope, erosion/accretion, mean sea level rise, and coastal protection,
population density and socioeconomic status...) and revealed that over 29.64% of the
considered coastline is at a very high risk. Recently, Torresan et al. [15] assessed
the vulnerability of the Mediterranean coasts of Egypt using a climate improved
coastal vulnerability index that proposed a new approach incorporating geologi‑
cal and socioeconomic parameters in addition to physical ones. This showed that
approximately 43 km² (1%) of the coastal area is at high and very high risk while
over 80% (4652 km²) has been classified at low vulnerability. In East Africa, an as‑
sessment of the evolution of the Kudichi coastline (Dar es Salam/Tanzania) through
superposition and analysis of aerial photographs of 1981, 1992 and 2002 showed
that between 1981 and 2002, 0.61 ha of land was eroded in the Kudichi area, with
an important accretion of about 2.21 ha, a loss 0.40 ha of mangrove area has been
also recorded [16]. In West Africa, Ozer et al. [17] used high resolution Google Earth
images to evaluate trends of coastline changes in Benin and Togo from 2000 to 2015
and revealed that 52% of the coastline is undergoing erosion processes while some
sections experience an accumulation (14%).
In Senegal, coastline retreat analysis involved 2 major approaches over time.
The first one was mostly oriented towards the interpretation of ancient geologi‑
cal map with reference to the sea level (marine transgression and regression). The
second approach dealt with the analysis of contemporary geospatial tools involv‑
ing aerial photographs, cadastral maps and recently satellite images. In the par‑
ticular area of Rufisque, coastline change studies were essentially based on the
analysis of iconographic documents (aerial photographs, topographic maps, ca‑
dastral maps, nautical charts, high resolution satellite images). Diallo [18], detect‑
ed a shoreline evolution rate of −1.29 m/year in Rufisque using topographic maps
(1933, 1948), cadastral map (1987), and non-rectified aerial photographs (1980).
In the same area, a coastline erosion of 1.3 m/year has been recorded by Sall [19]
by analyzing cadastral maps (1933, 1945) and a non-rectified aerial photograph
of 1980 while Niang -Diop [20] used non-rectified aerial photographs of (1959,
1968, 1972, 1976, 1980) to come up with −1.2 m of annual coastal change. Dieye [21]