Historiography on imperial mapping has never dealt with the sea as ardently or efficiently as it has with cartography on land. There have been good reasons for this. Approximately 90 per cent of the earth’s land mass came to be controlled by Europeans by 1914, and historians no doubt felt they had their hands full in trying to explain these terra firma conquests alone. Land was the ‘ground zero’ of cultural contact; surely the terrestrial realm was the best place to formulate interpretations of domination. Yet these processes of conquest and incorporation were also very important by sea, and epistemological translations of ‘space’ into maps also took place in this realm. This happened globally, but it especially happened in archipelagic settlings, such as were found in island Southeast Asia (the area currently comprised by Indonesia, Malaysia, Singapore, Brunei, and the Philippines). Here a ‘rounding off’ of sorts took place, as Europeans hydrographically cordoned off empires that were separated by open sea. Colonial powers eyed each other warily in these arenas, competing and sometimes also cooperating in the maritime division of the world. Contemporary historians have begun to peer at these mapping processes as well, looking at piracy as a form of resistance against the expanding colonial state; Japanese maritime surveying as a precursor to later armed aggression in Southeast Asia; and other such themes. Scholars, in fact, are now going back to the archives to re-examine the sea as a site of complicated cultural exchange. These new enquiries tie together imperialism, science, and the colonial interface in a variety of places and contexts.

This chapter will contribute to this burgeoning literature by examining the intertwined roles of hydrography, technology, and coercion in late nineteenthcentury Southeast Asia. I focus specifically on the waters of what we would now call Malaysia, Singapore, and Indonesia, which stretched from Aceh east to New Guinea, and from Java north to Sulu. In this vast maritime domain, the size of the continental United States, improvements in hydrographic knowledge went hand in hand with the advancing imperial presence. Though the evolution of sea maps was partially conditioned by expanding trade (metropoles, after all, knew that greater hydrographic knowledge equalled fewer marine disasters, and hence more revenue), this evolution was usually linked to colonial expansion as well. We will view these inter-relationships in three sections.