The Elements of Surveying and Geodesy |
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accuracy adjustment alidade angular base line bearing bubble calculated carried centre line chain line circumpolar star clamped coincidence contour contour lines convenient correct cross-webs curve diaphragm difference direction dumpy level earth error eyepiece feet field book fixed given ground height horizontal angle horizontal axis horizontal circle inches instrument intercept intersection length line of collimation line of sight marked means measured meridian method miles mirror moved necessary needle obtained offsets ordinary Ordnance Survey pair perpendicular placed plane table plotting plumb line pole position possible radius range reading right angles rotated scale seen sextant shaft shown on Fig side slope spirit level staff star station steel superelevation surface survey surveyor tacheometer tacheometry taken tangent screw tape telescope theodolite transit traverse triangle tripod tube vernier plate vertical axis vertical circle vertical line webs wire zero
Popular passages
Page 49 - All the interior angles of any rectilineal figure, together with four right angles, are equal to twice as many right angles as the figure has sides.
Page 174 - Thus the sines of the angles of a spherical triangle are proportional to the sines of the opposite sides.
Page 174 - The sum of the three angles of a spherical triangle exceeds two right angles by an angle which bears the same proportion to four right angles that the area of the triangle bears to the surface of the hemisphere.
Page 12 - In a right-angled triangle, the square on the hypotenuse is equal to the sum of the squares on the sides containing the right angle 59 THEOREM 30.
Page 190 - The latitude of a place on the earth's surface is its angular distance from the equator, measured on...
Page 81 - ... perpendicular to the plane of the instrument. If the reflected image drops, the glass is leaning backward; if it rises, forward. The adjustment is made by means of a key on the back, the latter being turned to the left if the image is dropping, and to the right if rising. The reflecting surface of the horizon glass should be perpendicular to the plane of the instrument. To test this, put in the telescope and point it towards a star, holding the instrument vertical, then move the instrument until...
Page 139 - She was also gratified by receiving a most affectionate and sympathizing letter from him, in his own hand, within a few weeks of her death. The interest felt about her on the continent of Europe, as well as in the United States of America, was indeed as warm and nearly as general as in her own country.
Page 32 - J{s(s — a) (s — b) (s — c)} gives the area of a triangle when the lengths of the three sides are known.
Page 182 - ... azimuth circle ; AB is a telescope mounted on Fig. 13. a horizontal axis and capable of two motions, one in altitude parallel to the circle abc, and the other in azimuth parallel to EFG. Hence it can be easily brought to bear upon any object. At m, under the eye glass of the telescope, is a small mirror placed at an angle of 45° with the axis of the telescope, by means of which the image of the object is reflected upwards, so as to be conveniently presented to the eye of the observer. At d is...