Cartography of India
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The cartography of India begins with early charts for navigation and constructional plans for buildings. Indian traditions influenced Tibetan and Islamic traditions, and in turn, were influenced by th
Details of the top of iron pillar, Qutub Minar, Delhi
Great Trigonometrical Survey
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The Great Trigonometrical Survey of India was a project that aimed to carry out a survey across the Indian subcontinent with scientific precision. It was begun in 1802 by the British infantry officer
Cartography of India
…out of question, and they never make use of scale of equal parts. The sea shores, rivers and ranges of mountains are represented by straight lines. The Great Trigonometric Survey, a project of the Survey of India throughout most of the 19th century, was piloted in its initial stages by William Lambton, and later by George Everest…
Index to the Great Trigonometrical Survey
The first triangulations across the Peninsula
Measurement of the Calcutta baseline in 1832 based on a sketch by James Prinsep. This shows surveyors stretching a chain on coffers supported on pickets. The chain is housed under shade to reduce errors due to thermal expansion, and is aligned using a boning telescope.
A zenith sector was an upward-facing telescope with accurate angle measurement scales. A star close to the zenith of known declination from the Pole Star was used to determine latitude, as a direct measurement of the Pole Star could be affected by refraction.