長江圖上的線索；自然地理與人文景觀的歷史變遷

本文考定一幅「長江圖」殘本的製作年代，進而探掘該國所蘊含的史料價值。該幅「長江圖」庋藏於臺灣中央研究院歷史語言研究所的明清內閣大庫檔案。儘管該圖業已修復，近年更經數位化處理，開放線上檢索瀏覽，惟因闕首殘尾，無法藉由標題或署款辨析其圖繪年代、涵蓋範圍與製作因緣。故而長年乏人問津，遑論將之運用於歷史地理的研究上。本文先從制度史入手，以「按驥索圖」的方式，藉已知推敲未知：彙整圖上所標示的各項官方建置，包括驛站、河泊所、巡檢司、衛所與城池等，對照相關史料記載與輿圖標示，檢視現存已知興遷存廢的紀錄，進而研判此圖繪製年代的上下時間斷限，並揣摩其製作目的。地圖有其時效性，地圖繪製的年代與其呈顯的歷史樣貌本為一體兩面，一旦確定該地圖在歷史中的時間座標，便可根據地圖的時效性來「按圖索驥」，探討地圖上的歷史：尋繹在此特定時空中自然變遷或人文發展的細節與線索。該長江圖乃以建置、交通與形勝為主要的構圖基架，此三者適足反映長江圖於制度史、環境史與文化史上的研究價值。若本文對該圖年代斷限的研判無誤，則這幅長江圖對當時地理水文、制度設置與文化景觀等，將足以作為參較勘照的重要依據。不僅有助於重新檢視過去聚訟紛紜的漢水改道問題，並可將漢口鎮興起的年代向前推移，甚至關於鸚鵡洲這座文化地標的浮沈滄桑，都可以在這幅長江圖上找到歷史的見證。

關鍵字

長江圖；官方建置；地緣政治；環境變遷；文化地標

並列摘要

This article investigates when a damaged map of the Yangtze River was originally created and explores its value as a historical source. The map is part of the Grand Secretariat Archives at the institute of History and Philology, Academia Sinica. While it has been restored, digitized, and made accessible online, portions of the original are lost to us. As a result, it has hitherto been impossible to use a title or cartographer's signature to ascertain its age, the circumstances of its creation, or exactly what it originally contained. For this reason, the document long attracted little attention and has not been used in the study of historical geography. Employing a methodology grounded in institutional history, this study deduces the unknown based on the known. It identifies each of the bureaucratic establishments indicated on the map, including postal relay stations, fishery tax offices, military inspectorates, military outposts (weisuo), and walled towns, and cross-references these with other historical sources. The paper examines extant records regarding the establishment, decommissioning, and relocation of these government establishments, and on this basis attempts to determine the likely range of dates for the creation of the map and to speculate about the purpose for which it was made. Arguably every map possesses an 〞expiration date〞 of sorts. The period during which a map was created and the history it represents are two faces of the same coin. Therefore, once a temporal coordinate has been fixed for a map, it becomes possible to deduce the document's 〞expiration date〞 and thereby explore its history, tracing the details of topographical change and cultural development that transect that time and space. In terms of its composition, this map of the Yangtze River is structured around government construction projects, transport networks, and topographical features, a fact that speaks to its potential value to research in the fields of institutional, environmental, and cultural history. Assuming the dating proposed in this paper is accurate, the map may serve as an important basis for the further study of contemporary hydrogeography, government institutions, and cultural landscapes of the region. It will not only facilitate reevaluation of the controversial issue of the historical changes in the course of the Han River, but may move back the date that Hankou was built, and even bear witness to the natural vicissitudes of 〞Parrot Isle,〞 a cultural landmark containing multiple layers of historical memory.