shravya: shravya: Ancient Maps

shravya: shravya: Ancient Maps: shravya: Ancient Maps Babylonian Imago Mundi  The oldest known world map. It is surrounded by a circular landmass showing  Ass...

shravya: Ancient Maps

shravya: Ancient Maps

Babylonian Imago Mundi 

The oldest known world map.

It is surrounded by a circular landmass showing Assyria, Urartu and several cities, in turn surrounded by a "bitter river" (Oceanus), with seven islands arranged around it so as to form a seven-pointed star. The accompanying text mentions seven outer regions beyond the encircling ocean.

Anaximander

Anaximander was credited with having created one of the first maps of the world, which was circular in form and showed the known lands of the world grouped around the Aegean Sea at the center. This was all surrounded by the ocean.

Hecataeus of Miletus 

Based on Anaximander's map ,he corrected and  enlarged.

Eratosthenes

Eratosthenes  drew an improved world map, incorporating information from the campaigns of Alexander the Great and his successors.Asia became wider, reflecting the new understanding of the actual size of the continent. Eratosthenes was also the first geographer to incorporate parallels and meridians within his cartographic depictions.

Posidonius

Posidonius  ideas about the positions of continents (many details couldn't have been known by Posidonius )

Strabo

Strabo is mostly famous for his 17-volume work Geographica, which presented a descriptive history of people and places from different regions of the world known to his era. , he claimed that a descriptive approach was more practical. Whole world maps according to Strabo are reconstructions from his written text.

 Pomponius mela 

 Pomponius divided the earth into five zones, of which two only were habitable, he asserts the existence of antichthones, people inhabiting the southern temperate zone inaccessible to the folk of the northern temperate regions due to the unbearable heat of the intervening torrid belt.

Ptolemy

The Ptolemy world map is a map based on the description of the world contained in Ptolemy's book Geographia, , the Geographia contains thousands of references to various parts of the old world, with coordinates for most, which seem to have influenced early Islamic maps, and allowed European .

Tabula Peutingeriana

The Tabula Peutingeriana (Peutinger table) is an itinerarium showing the cursus publicus, the road network in the Roman Empire.

Marinus of Tyre

Marinus   of Tyre. His chief legacy is that he first assigned to each place a proper latitude and longitude; he used a "Meridian of the Isles of the Blessed(Canary Islands or Cape Verde Islands)" as the zero meridian

Ancient Maps

HISTORY OF NAVIGATION

ODOMETER
   

  

• An instrument that indicates distance travelled by a vehicle.

• According to Encyclopedia Britannia, "About 15 BC, the Roman architect and engineer Vitruvius mounted a large wheel of known circumference in a small frame,It was, in effect, the first odometer.

• An advanced GPS odometer can accurately reveal the distance traveled to within 1/100 of a mile .
• A GPS with odometer mode is also an excellent and inexpensive means to verify proper operation of both the speedometer and odometer mounted in a vehicle.

MAGNETIC COMPASS

• A compass is a navigational instrument that measures directions in a frame of reference that is stationary relative to the surface of the earth
• The magnetic compass was invented during the Chinese Han Dynasty between the 2nd century BC and 1st century AD, and was used for navigation by the 11th century.

•  This is a working model of the first instrument known to be a compass. The spoon or ladle is of magnetic lodestone, and the plate is of bronze (non conducting metal). The circular center represents Heaven, and the square plate represents Earth. The handle of the spoon representing the Great Bear, points south.The plate bears Chinese characters which denote the eight main directions of north, north east, east, southeast, south, southwest, west, northwest, and symbols from the I Ching oracle books which were correlated with directions. Separately marked are the finer gradations of twenty-four compass points, and along the outermost edge are the twenty-eight lunar character representations. Rather than navigation, these simple direction pointers were likely used for geomancy or Fung Shui, the technique of aligning buildings according to forces of nature.

• DRAWBACK:The problem of magnetic variation ,which is later compensated by gyroscopes.

MARINERS ASTROLABE

• The Astrolabe:   An instrument with a past and a future

• The mariner's astrolabe, also called sea astrolabe, was an inclinometer used to determine the latitude of a ship at sea by measuring the sun's noon altitude (declination) or the meridian of a star of known declination.

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• . The mariner's astrolabe needed to be suspended vertically in order to measure the altitude of the celestial object. 

• DRAWBACKS:
• It meant it could not be used easily on the deck in windy conditions.
•  It could not easily be used to measure the angle between two objects, which was necessary for longitude calculations by the lunar distance method.
•  Another limitation was that the instrument's angular accuracy was directly proportional to the length of the alidade, which was not very long.

QUADRANT

• It is used to determine the altitude of a heavenly body.
•  It is originally used to find the eclipse of sun or to forecast someone's fate from the stars 
• An instrument, usually containing a graduated arc of 90°,used in astronomy, navigation, etc.., for measuring altitudes

GYROSCOPE/GYRO-COMPASS

• A gyroscope is a device for measuring or maintaining orientation, based on the principles of angular momentum.
• The earliest known gyroscope-like instrument was made by German Johann Bohnenberger, who first wrote about it in 1817. At first he called it the "Machine".

GYRO-COMPASS

• A gyrocompass­  is a type of non-magnetic compass which is based on a fast-spinning disc and rotation of our planet to automatically find geographical direction
• The first, not yet practical, form of gyrocompass was patented in 1885 by Marinus Gerardus van den Bos.
• A gyrocompass is a heading sensor which continuously indicates the horizontal angle from true north to the ship's fore and aft datum line
• ADVANTAGES:

• No maintenance, compared to a standard gyrocompass which needs both regular maintenance and calibration.
• Short Setting Time and easy installation.
• JRC - JRL 20 and JLR 30 gps compass antenna is a low-cost alternative to conventional spinning-mass and fiber-optic gyrocompasses.

MARINE CHRONOMETER

• A marine chronometer is a clock that is precise and accurate enough to be used as a portable time standard; it can therefore be used to determinelongitude by means of celestial navigation.
•  it is necessary and sufficient to know the latitude, longitude and altitude. ..!!!
  
  
  
  
  

• John Harrison (24 March 1693 – 24 March 1776) was a self-educated English clockmaker. He invented the marine chronometer, a long-sought device in solving the problem of establishing the East-West position or longitude of a ship at sea.

ARABIAN KAMAL

• The word kamal can be translated by “guide” or “road”, this is a very old navigation instrument, specially well adapted to take the height of the polar or other circumpolars stars.
• A kamal is a celestial navigation device that determines latitude.

SEXTANT

• A sextant is an instrument used to measure the angle between any two visible objects. 
• Its primary use is to determine the angle between a celestial object and the horizon which is known as the altitude

• ADVANTAGE :measurement is relative to the horizon  rather than relative to the instrument.
• GPS!There's no way around it: Celestial navigation using a sextant is a complex and involved process that involves a fair amount of calculating, correcting, referring to tables, knowledge of the heavens and the Earth, as well as a lot of common sense. (No wonder it's been so quickly replaced by the satellite-dependent Global Positioning System, or GPS!)

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