The records preserved in each city were examined, topographical information was diligently collected, and the Jesuit fathers checked their triangulation by meridian altitudes of the sun and pole star and by a system of remeasurements.
St Petersburg, again, is connected with Greenwich by European systems of triangulation; and the Greenwich meridian is adopted by Russia as the zero for all her longitude values.
But beyond the eastern shores of the Caspian no system of direct geodetic measurements by first-class triangulation has been possible, and the surveys of Asiatic Russia are separated from those of Europe by the width of that inland sea.
The astronomical observatory at Tashkent is adopted for the initial starting-point of the trans-Caspian triangulation of Russia; the triangulation ranks as second-class only, and now extends to the Pamir frontier beyond Osh.
The close of the 19th century witnessed the forging of the final links in the great geodetic triangulation of India, so far as the peninsula is concerned.
In connexion with the Indian triangulation minor extensions carried out on systems involving more or less irregularity have been pushed outwards on all sides.
The latter continued the Pamir triangulation, which had been carried across the Hindu Kush by Colonels Sir T.
The mission of Sir Francis Younghusband to Lhasa in 1904 resulted in an extension of the Indian system of triangulation which finally determined the geographical position of that city, and in a most valuable reconnaissance of the valleys of the Upper Brahmaputra and Indus by Captains C. H.
The primary triangulation was only completed in 1858, but in the meantime, in 1791, the detail survey had begun.
The maps are based upon the cadastral plans (1: 1000), thoroughly revised and connected with the triangulation of France and furnished with contours at intervals of 5 m.
The Specialkarte of Austria-Hungary on a scale of r:75,000 (765 sheets), based upon a triangulation and cadastral surveys (1816-1867), was completed in 1889, and published in heliogravure.
1875), is based upon a triangulation (1809-1833) and surveys on a scale of 1:25,000 for the lowlands, r :50,000 for the alpine districts, and was published (1842-1865) on a scale of r:roo,000.
The new survey of the Netherlands, based upon General Krayenhoff's primary triangulation (1802-1811) was completed in 1855.
The primary triangulation was completed in 1880, a topographical map coloured geologically (1 :200,000) was published 1889-1897, and in addition to this there are being published an agronomical map on a scale of 1:100,000 (since 1887) and others.
It is based upon a careful triangulation, superintended by Sir D.
It is based upon a triangulation by the U.S. Coast and Geodetic Survey.
A member of his expeditions, de Flotte Rocquevaire, made a triangulation of part of the western portion of the main Atlas, his labours affording a basis for the co-ordination of the work of previous explorers.
The first group comprises such subjects as land-surveying; here the measurements in the elementary stages take place in a plane, and the consideration of volumes necessarily constitutes a later stage; and the figures to be measured are mostly not movable, so that triangulation plays an important part.
This triangulation was the beginning of the great trigonometrical survey which has since been extended all over the country.
This and other points on the route were marked by buoys laid after careful triangulation by Capt.
In 1878 a map of the park based upon triangulation was drawn up by the Hayden survey, and in 1883-85 a more detailed map was made by the United States Geological Survey, and a systematic study of its geological phenomena was instituted.
This is the shallowest part, barely reaching a depth of 20 fathoms. It is being gradually 1 By the triangulation of 1840 its level was found to be 84 ft.
The Caucasus triangulation of 1860-1870 gave 89 ft.
These again have been connected by links of more or less regularity, so that, if the Baluchistan triangulation lacks the rigid accuracy of a " first class " system, it at least supports good topography on geographical scales.
Since then other travellers have visited the Pamirs, but the junction of the Russian and British surveys (the latter based on triangulation carried across the Hindu Kush from India) disposes of any further claim to the honours of geographical exploration.
(Russian triangulation), and on the east by the Talish mountains (9000 ft.).
From 1817 he directed the triangulation of Holstein, to which a few years later was added a complete geodetic survey of Denmark (finished after his death).
Ex Ploration The progress of geodetic surveys in Russia had long ago extended across the European half of the great empire, St Petersburg being connected with Tiflis on the southern slopes of the Caucasus by a direct system of triangulation carried out with the highest scientific precision.
Exact surveys in Russia, based upon triangulation, extend as far east as Chinese Turkestan in longitude about 75° E.
In India geodetic triangulation furnishes exact sur- the basis for exact surveys as far east as the eastern veys in boundaries of Burma in longitude about loo E.
But while we have yet to wait for that expansion of principal triangulation which will bring Asia into connexion with Europe by the direct process of earth measurement, a topobetween graphical connexion has been effected between Russian Russ/an and Indian surveys which sufficiently proves that the and deductive methods employed by both countries for the Indian determination of the co-ordinate values of fixed points so surveys.
From the great Indus series of triangles bases have been selected at intervals which have supported minor chains of triangulation reaching into the heart of the country.
Lefebvre, charged (1839) with political and geographical missions, and Captains Galinier and Ferret, who completed for him a useful triangulation and survey of Tigre and Simen (1840-1842).