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This map uses a variety of methods to aid navigation, including a rhumbline network (a web of lines to help plot routes). The numbers on the sea surface indicate depth (bathymetry), and the drawings of mountains (elevations) were used as landmarks.

This early 18th century maritime map charts the waters between the islands of Java, Madura and Bally (Bali). The web of lines is a rhumbline network, while the numbers indicate sea depth (bathymetry), both used to aid navigation.

Hand-drawn portolan (nautical) chart, featuring a rhumbline network (the web of interconnected lines), bathymetry (sea depth), shoals and reefs, names of coastal settlements, and an elevation (side view) of a mountain at the north tip of Borneo.