Etude De L’évolution Du Trait De Côte À L’aide De L’outil Mobitc : Cas Du Littoral De Grand-Bassam

This study proposes an assessment of the historical coastline (TDC) mobility of the Ivorian coastline, specifically the Grand-Bassam coastline (Côte d'Ivoire), and suggests reflections on the sustainable management of the coastal environment in Côte d'Ivoire, taking into account coastal erosion. The objective is to evaluate, using the MobiTC software, the spatio-temporal and statistical evolution of the morphology of the Grand-Bassam coastal zone in order to plan appropriate coastal developments. Specifically, it is to extract images on google earth, to treat them under MobiTC and to analyze the rate of spatio-temporary and statistical evolution of coastlines. To do this, data from QuickBird images provided by Google Earth from 1984, 1988, 1992, 1996, 2000, 2004, 2008, 2012 and 2016 in the study area were used. Different software was used for image processing. The ENVI 5.1 software allowed georeferencing and thresholding to make the images superimposable and highlight the baseline. The digitization of the images was done with ArcGis software. The QGIS 2.18 software was used to convert the .shp files to the mid / mif format of the MobiTC software. The latter makes it possible to understand the statistical evolution of the coastline dynamics from the creation of a baseline, the skeleton of envelopes and traces. The variations observed between 1984 and 2016 show a fattening of 0.23 m / year in some sectors and an erosion rate of 0.34 m / year in other sectors. It is noted that 62.79% of the coastline is accretion and 37.21% is eroding

Cartographie De La Dynamique Du Trait De Cote A Grand-Lahou : Utilisation De L’outil « Digital Shoreline Analysis System (Dsas)»

Like many coasts, coastal erosion is evident on all the Ivorian coast and is characterized by the destruction of physical assets (infrastructure, habitat and sightseeing). Especially in Grand-Lahou, it threatens a fishing village located on a strip of land 200 meters separating the Atlantic Ocean from the Tadjo lagoon and facing the mouth of the Bandama River. To contribute to the choice of sustainable coastal development in Grand-Lahou, this study aims to characterize the dynamics of the coastline by performing coastal erosion map locally for the best appreciation of the erosion phenomenon. To do this, the GIS which consisted of compilation of coastlines data from Landsat images from 1998, 2001, 2005, 2009, 2011 and 2014 in the study area. The dynamic of the coastline in this zone was done through the Digital Shoreline Analysis System (DSAW). The variations observed between 1998 and 2014 show a coastline fattening at an average rate of 2.09 m / year in the west of the river mouth before Lahou-Kpanda village and erosion with a speed of 0.84 m / year on rest of the shore after Lahou Kpanda village