The point where a vertical line through the optical centre of the camera lens intersects the ground, is known as
Ground principal point
Ground plumb point
Iso-centre
Perspective centre
Correct Answer :
B. Ground plumb point
Related Questions
If the altitudes of a star at its upper and lower transits are 60° 30' and 19° 30' respectively, the latitude of the place, is
30°
35°
40°
45°
Pick up the correct statement from the following:
Sidereal time at any instant is equal to the hour angle of the first point of Aries
Local sidereal time of any place is equal to the right ascension of its meridian
Sidereal time is equal to the right ascension of a star at its upper transit
All the above
The angle between the axis of earth and the vertical at the station of observation is called
Astronomical latitude
Astronomical co-latitude
Co-declination of star
Declination of star
In triangulation surveys
The area is divided into triangular figures
Control stations are located from which detailed surveys are carried out
Sides are not measured excepting the base line
All the above
Pick up the correct statement from the following:
North end of the polar axis is known as North Pole
South end of the polar axis is known as South Pole
Point where polar axis when produced northward intersects the celestial sphere, is known as north celestial pole
All the above
Pick up the correct statement from the following. The difference between the longitudes of the places is obtained.
By subtracting their longitudes if places are in the same hemisphere
By adding their longitudes if places are in the different hemispheres
By subtracting the sum of their longitudes exceeding 180° from 360° if places are in different hemispheres
All the above
In a spherical triangle ABC right angled at C, sin b equals to
sin c sin B
cos c cos B
tan c tan B
sin c cos B
The station which is selected close to the main triangulation station, to avoid intervening obstruction, is not known as
Satellite station
Eccentric station
False station
Pivot station
Pick up the correct statement from the following:
The horizontal direction of the pole is called astronomical north
The angle between the direction of true north and the direction of a survey line is called astronomical bearing
The astronomical bearing is generally called azimuth
All the above
In a tropical year, the numbers of sidereal days are
365
365.2224
365.2422
366.2422
The slotted template method
Is prepared, by graphical method
Is suitable for large areas with less control
Is rapid and accurate
All the above
The difference in longitude of two places expressed in time is equal to the difference in their
Sidereal time
Apparent solar time
Mean solar time
All the above
The principal line is the line joining the principal point and
Nadir
Isocenter
Perspective centre
None of these
Pick up the incorrect statement from the following:
In truly vertical photographs without relief angles are true at the plumb point
In tilted photographs without relief, angles are true at the iso-centre
In tilled photographs with relief, angles are true at the principal point
None of these
The angle between the observer's meridian and declination circle of a heavenly body, is known as
Hour angle
Azimuth
Right ascension
Declination
Longitude of a place is the angular distance between the meridian of the place and
The standard meridian
The international date line
That of Greenwich
Both (a) and (c) of above
If S is the sum of three angles of a spherical triangle, the spherical excess equals
S - 90°
S - 180°
S - 270°
S - 360°
The following points form a pair of homologous points:
Photo principal point and ground principal point
Photo isocenter and ground isocenter
Photo plumb point and ground plumb point
All the above
The method of surveying by triangulation was first introduced by the Dutchman Snell in
1600
1615
1630
1650
If v, t and f/H are the ground speed of the aircraft, the shutter speed of the camera and the scale of the photograph respectively, then the amount of image displacement
i = v. t. H/f
i = v. f/t. H
i = v. t. (f/H)
i = t. H/v. f
Right ascension of a heavenly body is its equatorial angular distance measured
Westward from the first point of Libra
Eastward from the first point of Aeries
Westward from the first point of Aeries
Eastward from the first point of Libra
α and β are the angles subtended by a point of elevation h at their air station with respective plumb points. Photo scale and focal length of the lens being S and f respectively. Parallax displacement of the point due to relief, is
h tan α/S
h tan β/S
h (tan α + tan β)/S
h (tan α - tan β)/S
On vertical photographs, height displacement is
Positive for points above datum
Negative for points below datum
Zero for points vertically below the air station
All the above
The station pointer is generally used in
Triangulation surveying
Astronomical surveying
Hydrographical surveying
Photogrammetric surveying
The displacement of the pictured position of a point of h elevation on a vertical photograph taken with a camera of 30 cm focal length, from an altitude of 3000 m, is
4.4 mm
5.5 mm
6.5 mm
7.5 mm
Perspective centre relates to
Parallel projection
Orthogonal projection
Central projection
None of these
The average eye base is assumed as
58 mm
60 mm
62 mm
64 mm
Triangulation surveys are carried out for locating
Control points for surveys of large areas
Control points for photogrammetric surveys
Engineering works, i.e. terminal points of long tunnels, bridge abutments, etc.
All the above
Rotation of the camera at exposure about its vertical axis, is known as
Swing
Tilt
Tip
None of these
A plate parallel is the line on the plane of the negative
Parallel to the principal line
Perpendicular to the principal line
Along the bisector of the angle between the principal line and a perpendicular line through principal plane
None of these