The net ground area of a vertical photograph 20 cm × 20 cm on scale 1 : 10,000 having overlaps 60% and 30%, is
0.50 sq km
0.56 sq km
0.60 sq km
0.64 sq km
Correct Answer :
D. 0.64 sq km
Related Questions
The zenith is the point on the celestial sphere
East of observer
West of observer
North of observer
South of observer
Rotation of the camera at exposure about its vertical axis, is known as
Swing
Tilt
Tip
None of these
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
23 cm × 23 cm photographs are taken from a flying height with a camera of focal length of 3600 m and 15.23 cm respectively. A parallax difference of 0.01 mm represents
1 m
2 m
4 m
8 m
The height displacement on a vertical photograph
Increases as the horizontal distance increases from the principal point
Increases as the ground elevation increases
Decreases as the flying height increases
All the above
Pick up the correct statement for horizontal photographs.
Parallel lines do not appear parallel in central projection
The two sides of a road meet at the vanishing point
The lines parallel to the negative plane are projected as parallel lines
All the above
The prime vertical passes through
The east point of the horizon
The west point of the horizon
The zenith point of the observer
All the above
The declination and right ascension of the sun becomes 23° 27' N and 90° respectively on
March 21
June 21
September 21
December 22
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
Pick up the correct statement from the following:
Refraction correction is zero when the celestial body is in the zenith
Refraction correction is 33' when the celestial body is on the horizon
Refraction correction of celestial bodies depends upon their altitudes
All the above
The position of a heavenly body on the celestial sphere can be completely specified by
Its altitude and azimuth
Its declination and hour angle
Its declination and right ascension
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°
Pick up the incorrect statement from the following:
Latitudes north of the equator are taken as positive
Latitudes south of the equator are taken as negative
Longitudes east of Greenwich are taken as negative
Longitudes west of Greenwich are taken as positive
The true and mean suns occupy the same meridian at the same time on
April 15
June 14
September 1
All the above
The negative sign is assigned to
Reduction to mean sea level
Correction for horizontal alignment
Correction for slope
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
To obtain photographs of an area of 1000 m average elevation, on scale 1 : 30, 000, with a camera of 30 cm focal length, the flying height is
4000 m
5000 m
6000 m
7000 m
The value of geo-centric parallax to be added to the observed altitude of sun is
9 cos α
9 sin α
9 tan α
9 cot α
Polaris is usually observed for the determination of the latitude when it is
At culmination
At elongation
Neither at culmination nor at elongation
Either at culmination or at elongation
In a tropical year, the numbers of sidereal days are
365
365.2224
365.2422
366.2422
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
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 angular distance of a heavenly body from the equator, measured along its meridian, is called
Declination
Altitude
Zenith distance
Co-latitude
For adjusting a quadrilateral whose both the diagonals are observed, the equations of conditions involved, are
Two angle equations and two side equations
One angle equation and three side equations
Three angle equations and one side equation
None of these
The method of surveying by triangulation was first introduced by the Dutchman Snell in
1600
1615
1630
1650
Pick up the in-correct statement from the following:
Correction for refraction is always negative
Correction for parallax is always positive
Correction for semi-diameter is always negative
Correction for dip is always negative
Homologous point is
Photo principal point
Ground principal point
Ground isocenter
All the above
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
If the image of a triangulation station of R.L. 500 m is 4 cm from the principal point of a vertical photo taken from an altitude of 2000 m, above datum, the height displacement will be
2 mm
4 mm
6 mm
10 mm
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°