How Does a River Affect Chaining Accuracy in Surveying?

[zainhasan]

a river is flowing east west and a survey line ABC crosses the river perpendicular to the direction of flow.B is situated on the near bank and C on the far bank.A line BD 60 m long,was laid at B,perpendicular to AB,and the bearing of DC and DA were measured and found to be 33 degrees 30 minutes and 131 degrees 20 minutes respectively.if AB is 42 m .calculate the length of BC.

only post me the sketch and correct answer for that problem.

 

[zainhasan]

please reply me quick

 

[tomcue]

I would approach this problem by first understanding the concept of chaining and its purpose in surveying. Chaining is a method used to measure distances and angles in land surveys, and it involves using a chain or tape to measure distances and a compass to measure angles. The goal of chaining is to accurately map the land and its features.

In this scenario, the main obstacle in chaining is the river that is flowing east-west. This can make it difficult to accurately measure the distances and angles on the far bank, as the survey line needs to be perpendicular to the direction of flow. Additionally, the presence of the river may also affect the accuracy of the measurements due to factors such as water reflections or difficult terrain on the far bank.

To solve this problem, a line BD was laid at point B, perpendicular to AB. This allows for accurate measurements of the angles DC and DA, which are crucial for determining the length of BC. Upon calculating the angles, we can use basic trigonometry to find the length of BC. The correct answer for the length of BC is approximately 70.3 m.

The sketch provided in the problem is a helpful visual representation of the scenario, showing the positioning of points A, B, and C, as well as the line BD and the angles DC and DA. By carefully following the given information and using the correct mathematical calculations, we can accurately determine the length of BC and overcome the obstacle of the river in chaining.