SURVEYING LECTURE 5

when do we use weighted measurements?

1. when some observations are better because of equipment

2. - - - - done during more favorable conditions

3. - - - have high precision thus having smaller standard deviation than other.

(-) means repeated words

interrelationship of errors (2)

1. SUMMATION OF ERRORS

2. PRODUCT OF ERRORS

probable error of the sum is given by the square root of the sum of the squares of the separate probable erros arising from several sources.

SUMMATION OF ERRORS

formula os summation of errors

PE sub s = +- squareroot of PE(1)² + PE(2)² + PE(3)² + …. + PE(N)²

for a measured quantity which is determined as the product of two other independently measure quantities.

PRODUCT OF ERRORS

formula of product of errors

PE(P) = +- squareroot of (Q(1) X PE(2))² + (Q(2) X PE(1))²