The survey that considers earths curvature into consideration is called

Mean sea level is established by taking the average height of tides in the sea over a period of

The line of sight of the telescope of a surveying instrument is called

The first reading taken on the staff after setting up the level

Error due to imperfect adjustment of level

Mistakes in manipulation - error in setting up the level, parallax, staff not vertical can be

GPS use which of the following technique

What measurements are taken in triangulation

1. What measurements are taken in trilateration