Surveying - Questions

1.
Errors
Four level circuits were run over four different routes. The elevation and error for each circuit is listed below. What is the most probably value of the benchmark’s elevation?

Route 1: 745.07 ± 0.02
Route 2: 745.22 ± 0.03
Route 3: 745.40 ± 0.08
Route 4: 745.16 ± 0.04

2.
Leveling
A level is placed where the height of the instrument above datum is 294.45 ft. The rod is held on a point 4000 ft away. And a reading of 4.65 ft is recorded.
a) Find the effect of the earth’s curvature on the rod reading
b) Find the effect of the atmospheric refraction on the rod reading.


3.
A 5 leg closed traverse is taped and scoped in the field, but obstructions make it impossible to collect all the readings. It is known that the general direction of EA is east west. Complete the field notes:

Leg north azimuth distance
AB 106.22° 1081.3
BC 195.32° 1589.5
CD 247.12° 1293.7
DE 332.37° ______
EA ______° 1081.3


4.
Photogrammetry
A camera with a focal length of 5 inches and a size of 10 in by 10 in is used to photograph an area from an altitude of 4500 ft above sea level.
a) If the average elevation is 600 ft, what is the average scale of the photo?
b) What is the ground area covered by a single photograph?
c) If overlap and sidelap are 50% and 30% respectively, what is the ground spacing between exposures?
d) same as c) what is the ground spacing between flight lines?
e) if the aircraft is moving at 325 mph ground speed, what is the time interval to the nearest 0.1 sec between exposures?
f) two points at elevation 650 ft appear 90 mm apart on the photo, what is the ground distance?
g) what elevation should a plane be flown to get an average scale of 1:10,000 if the elevation is 1100-1300 ft above sea level.