Coordinates And Its Types With Diagram

Coordinates are defined as the distance of a point form some reference point. Coordinates The reference point is called the origin. Any point of a traverse can be taken as the origin.

What is Coordinates ?

Coordinates And Its Types With Diagram

Coordinates are defined as the distance of a point form some reference point. The reference point is called the origin. Any point of a traverse can be taken as the origin. This origin can be any point outside the traverse also. The coordinates in any survey are determined parallel to north and south of the magnetic meridian. These are taken perpendicular to the meridian. i.e., in east- west direction also . the coordinate taken parallel to the meridian are called latitudes and those taken perpendicular to the meridians are called departures the latitudes taken to the north is considered as positive n while latitude towards south and departure toward west are considered negative .
The Latitude taken to the north is known as Northing latitudes while the departures taken to the east are termed as Easting.

Coordinates And Its Types With Diagram

if the reduced bearing of a survey line is known then the latitudes and departures are calculated by the following formulae. It is to be noted that if the bearing is given in W.C.B then it is first changed to R.B.

L= l cos 0 , l sin 0
L = D2 + L 2,0 = tan-1 D/L
Where,
L = latitude
D = departure
l =Length of survey line
0 = Reduced bearing of survey line

Signs of Latitudes and Departures

Whole circle bearing

(W.C.B)

Quadrant Sign of Latitude Sign of Departure

00 – 900

1st or NE

+

+

900 – 1800

2ND SE

+

180 0– 2700

3RD SW

 2700 – 3600

4TH NW

+

Types of coordinates.

There are two type of coordinate .

1. Consecutive coordinate
2. Independent coordinates

1.Consecutive coordinate
If the latitudes of a line in a survey are started form the origin then these coordinate are called consecutive coordinate . these coordinate can be calculated from the length of a line. These coordinate s are not related with those of another line.

2.Independent coordinates
These coordinates are measured with reference of some fixed point. The fixed point is known as origin. These coordinate are the algebraic sum of all the coordinate of all the previous lines. In this system the coordinate of some point are called total latitude and total departure.Coordinates And Its Types With Diagram

According to above diagram the consecutive and the independent coordinate are follows ;-

Consecutive coordinate

Independent coordinate

Line

Latitude

Departure

Point

Latitude

Departure

AB

+(A2 B2)

+(A1 B1)

A

OA2

OA1

BC

+(B2 C2)

+(B1 C1)

B

OB2

OB1

CD

+(C2 D2)

+(CD1)

C

OC2

OC1

DE

+(D2 E2)

+(D1 E1)

D

OD2

OD1

EA

+(E2 A2)

+(E1 A1)

E

OE2

OE1

 

Coordinates are defined as the distance of a point form some reference point. Coordinates The reference point is called the origin. Any point of a traverse can be taken as the origin.

 

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