What is a cross-staff in survey?
What is a cross-staff in survey?
The cross staff is used to set out the perpendicular directions for offsets. In this survey, the base line runs through the center of the area, so that the offsets are left or right side of base line are fairly equal. To check accuracy length of the boundary lines may also be measured.
How do you calculate the area of a cross-staff survey?
- Cross Staff Survey. Anirudh Kumar.
- Area of trapezium ABdb =
- Area of triangle BYd = x Base x Height.
- Area of triangle eYC = x Base x Height.
- Area of trapezium eCDc =
What is the cross-staff used for?
The cross-staff is an instrument used to measure angles and altitudes, consisting of a trigonometrically graduated staff and one or more perpendicular vanes moving over it.
How many types of cross-staff are available?
10. How many types of cross staff are available? Explanation: The three types are open cross staff, French cross staff and adjustable cross staff. Open cross staff has two vertical, opposite slits.
Which cross-staff is more accurate?
An optical square is used for the same purpose as the cross-staff, but it is more accurate.
What is the Open cross-staff?
The Open cross-staff consists of a long staff with a perpendicular vane which slides to and fro upon it. These open frame tripods are comes with lemon yellow powder coated and silver anodized. Features: Used to measure the altitude of the sun. Used as a navigation instrument.
What is line Ranger?
Line ranger is an optical instrument used for locating a point on a line and hence useful for ranging. It consists of two isosceles prisms placed one over the other and fixed in an instrument with handle.
What is metric chain?
metric (SI) units. 20.1168 m. The chain is a unit of length equal to 66 feet (22 yards). It is subdivided into 100 links or 4 rods. There are 10 chains in a furlong, and 80 chains in one statute mile.
How do you use Jacobs staff?
To measure bed thickness, place the Jacob’s Staff on the bedding plane at the base of the beds you want to measure. Next align the staff at right angles to bedding and sight downdip, perpendicular to strike, to the beds.
Which of the following is not a common form of cross-staff?
It consists of either a frame or box with pairs of vertical slits and is mounted on a pole shod for fixing in the ground. 2. Which of the following is not a common form of cross staff? Explanation: The common forms of cross staff are open cross staff, french cross staff, adjustable cross staff.
What is the procedure of cross staff survey?
Procedure : To start the cross staff survey ,a chain line is run through the centre of the area to be surveyed .it is divided into right angled triangles and trapezoids .The perpendicular to the boundary are taken in order of their chainages.
How to determine the area of a given field by cross staff?
AIM: To determine the area of a given field with define boundary by conducting cross staff survey. 2. INSTRUMENTS REQUIRED: Metric Chain of 20m/30m – 1 no, Tape -1 no, Ranging rods – 4 nos., Arrows – 10 nos., and Cross staff – 1 no.
What is chain surveying and how does it work?
Chain surveying is the type of surveying in which only linear measurements are made in the field. The main principle of chain surveying or chain triangulation is to provide a framework consist of number of well-conditioned triangles or nearly equilateral triangles. It is used to find the area of the field.
What is the best way to do small surveys?
Small, “localized” survey work can easily and quickly be done using a level instrument. Potential weir sites, locations where road crossings, division boxes, etc. have to be built, can be mapped by taking a few cross sections in the field and working it out in the office.