Wednesday, October 21, 2015

Bathymetrical chart of the Oceans in 1899

showing the "Deeps,", according to Sir John Murray
It was published by the Royal Geographical Society in 1899. Scale [ca. 1:100,000,000].
The image inside the map neatline is georeferenced to the surface of the earth and fit to the 'World Gall Stereographic' projection with the central meridian at 20.00000 degrees west.
All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, index maps, legends, or other information associated with the principal map.
This map shows features such as drainage, shoreline features, and more.
Relief shown by hypsometric tints.
Depths shown by gradient tints. 
The only physiographic feature he named were deeps, defined as area of the seafloor believed to have depths greater than 3000 fathoms. 

From ICA

Ocean exploration was a key scientific objective in the late 1800s.
Any number of oceanographic, biological, chemical, geological and physical discoveries had been made and one of the preeminent scientists was John Murray.
The results of his voyages on H.M.S. Challenger led to this map, the first to make its focus the deeps, what occurs underneath the surface rather than previous voyages and explorations that were concerned with coastal and shallow waters.
Murray recognized that measurement at depth required correct and operational instrumentation because it was indirect measurement that was required.
Why was this necessary?
Accurate survey of the ocean floor was paramount to the correct siting of telecommunications cables across the ocean basins.
For that you needed an accurate map.

This map for the first time showed ‘the deeps’ according to Murray.
The mid-atlantic ridge is clearly shown as are areas of the Atlantic Ocean that are greater than 3,000 fathoms deep.
In many ways, Murray, the Challenger expeditions and this map were critical in the establishment of oceanography as a distinct branch of science.

Murray went beyond calculating bathymetry though, he estimated temperature of the ocean floor as distinct to the surface as well as the amount of light penetrating the darkness and the impact on flora and fauna and marine deposits.
The map uses subtle bathymetric tinting and is the first to officially name many of the deep ocean floor troughs.
It’s not a complex map but it’s apparent simplicity belies the efforts and science that went into making it.

Maps do not need to appear complex.
They can be used effectively to communicate scientific discovery, accuracy and new knowledge.
This map, for its time, was revolutionary and was the first to give us a sense of what lies beneath the surface of the vast expanse of seas and oceans.

Alexander Supan's world map of 1899 showing both deeps and bathymetric highs of the World Ocean.
Note difference in names between Supan and Murray in previous map. 
upan's naming methodology prevailed in the Twentieth Century.
Note also the Karolinen Graben running parallel to the Caroline Islands as opposed to the correct orientation of the Mariana Trench. 

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