十八世纪后叶,英国的军舰便力图觅取各种各样的海图。那时,除了格林韦尔的《沿海航行指南》和东印度公司出版的为数不少的可靠的关于印度洋和东印度海区的海图外,几乎就没有什么官方出版的正式海图了。当时,英国海军部指定军舰上将亚历山大·达尔林普尔的水文图作为主要的海图资料留存。那时,默尔克·麦肯齐叔侄和格雷姆·斯彭斯也是海图的主要提供者。麦肯齐自1750年受雇于海军 In the late eighteenth century, the British warships tried to find a variety of charts. At that time, with the exception of Greenwell’s Guide to Coastal Navigation and the many reliable charts of the Indian Ocean and the East Indian Sea, published by East India Company, there were virtually no official published charts. At that time, the British Hydrographic Department of the admiral named Alexander Darling Polar hydrograph as the main chart data retained. At that time, the nephews of Murk McKenzie and Graeme Spence were also the main providers of charts. Mackenzie was employed by the Navy in 1750