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
Correct Answer :
D. All the above
Related Questions
The moon rotates round the earth once in every
29 days
29.35 days
29.53 days
30 days
The difference of height of two points whose parallax difference is 0.8 mm on a pair of stereo pair taken from a height H is 100 m. If mean photo base is 95.2 mm, the flying height is
8,000 m
10,000 m
12,000 m
14,000 m
The zenith is the point on the celestial sphere
East of observer
West of observer
North of observer
South of observer
If δ is the declination of the star and φ is the latitude of the observer, then the azimuth of the star at elongation is given by
sin z = sec φ . cos δ
cos z = sec φ . cos δ
tan z = sec φ . cos δ
None of these
With standard meridian as 82° 30' E the standard time at longitude 90° E is 8 h 30 m. The local mean time at the place will be
7 h 00 m
7 h 30 m
8 h 00 m
9 h 00 m
Perspective centre relates to
Parallel projection
Orthogonal projection
Central projection
None of these
The rate of change of parallax dp/dh with respect to change in h, may be expressed as
fB/(H - h)
fB/(H - h)2
fB/(H + h)
fB/(H + h)2
At eastern elongation, the pole star moves
Eastward
Westward
Northward
Southward
Pick up the in-correct statement from the following:
Apparent solar time is measured from the lower transit of the true sun
Mean solar time is measured from the lower transit of the mean sun
Sidereal time is measured from the lower transit of the first point of Aries
Sidereal time is measured from the upper transit of the first point of Aries
Homologous points are
Opposite corners of a photograph
Nodal points of the camera lens
Corresponding points on the ground and photograph
Plumb points of stereo pair of photographs
The elevation of the star at elongation is obtained by
sin α = sin φ cosec δ
sin α = sin φ sec δ
sin α = cos φ sec δ
sin α = cos φ cosec δ
If two points differing by 1° of latitude and of the same longitude is 110 km apart on the earth, then two astronomical positions on the moon is about
10 km
25 km
30 km
50 km
At lower culmination, the pole star moves
Eastward
Westward
Northward
Southward
The scale of a tilted photograph of focal length f taken from an altitude H, along the plate parallel through principal point is
f/H sec θ
f sec θ/H
f/H
f/H cos ½θ
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 negative sign is assigned to
Reduction to mean sea level
Correction for horizontal alignment
Correction for slope
All the above
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
The parallax of a point on the photograph is due to
Ground elevation
Flying height
Length of air base
All the above
If the general ground level of any area is 10% of the flying height, the principal points may be used as the centres of radial directions for small scale mapping even in tilted photograph up to
1°
2°
3°
4°
If δ is the declination of the Polaris and λ is the latitude of the place, the azimuth of the Polaris, is
cos δ/cos λ
cos (90° - δ)/cos (90° - λ)
sin (90° - δ)/sin (90° - λ)
tan (90° + δ)/tan (90° + λ)
The average eye base is assumed as
58 mm
60 mm
62 mm
64 mm
The maximum error in radial line assumption, is
h/H f tan θ
h/H f² tan θ
h/H f² sin θ
h/H f cos θ
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
If 16 flight lines are run perpendicular to an area 30 km wide, their spacings on a photographical map on scale 1 : 50,000 , will be
1 cm
2 cm
3 cm
4 cm
To have greatest coverage of the area, the type of photography used, is
High oblique
Low oblique
Vertical
None of these
If the equatorial distance between two meridians is 100 km, their distance at 60° latitude will be
1000 km
800 km
600 km
500 km
For plane ground the scale of a vertical photograph will be same as that of a tiled photograph along the photo parallel through
Isocenter
Plumb point
Principal point
None of these
The declination and right ascension of the sun becomes 23° 27' N and 90° respectively on
March 21
June 21
September 21
December 22
In observations of equal precision, the most probable values of the observed quantities are those that render the sum of the squares of the residual errors a minimum, is the fundamental principle of
Gauss' Mid Latitude formula
D'Alembert's method
Legendre's method
Least square method
Pick up the correct statement from the following:
The star's movement is apparent due to the actual steady rotation of the earth about its axis
The stars move round in circular concentrated parts
The centre of the circular paths of stars is the celestial pole
All the above