Historical coastal maps: importance and challenges in their use in studying coastal geomorphology

Abstract

Historical maritime maps such as navigation charts, bird’s-eye view maps and plan maps preserve useful coastal information of the time. Through the archival survey of such documents, a large number of charts and maps (particularly of large and medium scale) have been found that were published from sixteenth-century CE onwards. These maps– depict manmade structures such as forts and other buildings visible to sailors approaching the coast; and mark geomorphic features such as spit, bar, shoal, delta; with appropriate shape, relative position and size. Understanding the geomorphic features present in these maps and analyzing them using remote sensing imagery, historical text and recent studies can immensely enhance knowledge of coastal geomorphic changes in the interim period. However, there are challenges in analyzing these maps, such as scale variability within or across the maps, date of publication versus survey, originality of map content (copied versus original), the importance of the place to the cartographer, the purpose of making the map, cartographic skills, style and methods, etc. The present study discusses the untapped potential of historical maritime maps and charts to understand coastal geomorphology along with the challenges one can confront while studying them and suggests ways to overcome them.