In surveying, fixed obstacles are best dealt with by?

In surveying, fixed obstacles such as buildings, trees or other immovable objects can interfere with the accuracy of measurements. The best way to deal with these obstacles is by laying offsets. Offsets are measurements taken at a right angle to the original line, which go around the obstacle and then rejoin the original line on the other side. This allows for accurate measurements to be taken without having to move the obstacles or work around them. The offset distance should be as short as possible to minimize any errors. Avoiding obstacles is not always possible, as survey lines need to be straight and follow the desired route. Using an abney level is helpful in determining the height of obstacles but doesn't provide a solution to the problem. Removing obstacles is not a practical solution, especially for fixed structures that cannot be relocated.