本研究的主要目的為使用遙測影像技術進行西甘比亞區域的土地覆蓋變遷監測，研究產製該區的土地覆蓋變遷圖，並關注於1985年到2013年間的都市成長情況。研究區範圍包含甘比亞西海岸區與部分的北岸區，緯度分布由北緯13o 03’ 到 13o 36’，經度範圍為西經16o 06’ 到 16o 36’ 之間。甘比亞的全國人口數為1,195,082 人，而63.49%的甘比亞居民居住於此，區域人口密度為478人/平方公里。 為分析需要，本研究蒐集了1985、1999、2013的Landsat影像進行地表覆蓋分類，並修正現有的土地覆蓋參考地圖以進行分類精度的評估。多時序的影像資料先進行空間資料分析處理:包括影像座標校正、以支援向量機(SVM)進行地物分類；後續分析包含了多時序土地覆蓋圖的建立，並求得分類地物類別每期的類型變動與其關聯的面積變化。研究結果顯示:研究區內的建物類別相對其他地物類別有著相對高程度的正增長，1985年為46.42平方公里，1999年增為97.35平方公里，而2013年則變為193.02平方公里，以上數據顯示了急遽增加的面積變化；此外，地表自然植被類別由1985年的1,184.22平方公里到2013年的929.69平方公里，研究數據分析顯示該類別的面積變化率呈現穩定地減少；而耕地類別的面積則略有些增加；紅樹林類別的分布與覆蓋面積從過去30年以來則維持相當地穩定。西甘比亞的人口壓力應是研究區內影響地表建物類別變遷增長的最重要驅力。因此，政府與其他利益攸關者應該建立可達成均衡合作與永續性自然資源管理的政策與策略。;The main objective of this research is aimed at producing multi-temporal land cover maps of the Western Gambia in order to monitor land-cover changes (LCC) using Remote Sensing techniques with a focus on urban growth during the period 1985 – 2013. The study area is the Western Gambia covering West Coast Region and part of North Bank Region lying between Latitudes 13o 36’ N and 13o 03’ N and Longitude 16o 54’ W and 16o 06’ W. About 63.49% of the country’s population resides here with a population density of 478 people per km2. For this purpose, multi-temporal Landsat images for 1985, 1999, and 2013 were acquired. The existing land cover reference maps collected and modified for accuracy assessment. These multi-temporal data were processed using spatial analysis tools of geo-referencing, Support Vector Machine (SVM) classification, and post- classification processes, to map the patterns and extent of land cover in the study area as well as determine the magnitude of changes between the years of interest. The result of the study showed that the built-up areas have been on a constant positive and mostly uncontrolled expansion from 46.42 km2 of the study area in 1985 to 97.35 km2 in 1999 and to 193.02 km2 in 2013. On the other hand, terrestrial vegetation has been on a steady decline, from 1,184.22 km2 in 1985 to 929.69 km2 in 2013, while the cultivation land experienced a slight increase in area. The mangrove forest is fairly stable in the past three decades. Population pressure is the major driving forces of LCC in the Western Gambia; therefore the government and other stakeholders should develop policies and strategies to achieve a balanced, coordinated and sustainable natural resources management.
