Скачать или смотреть Lecture 14 Reciprocal levelling

This lecture (0:01-2:59) covers reciprocal leveling, a surveying technique used when large obstructions like rivers, ponds, or valleys are present, preventing direct measurement. The method helps eliminate errors caused by curvature, refraction, and collimation (2:49-3:03).

Here's a breakdown of the key points:

Necessity of Reciprocal Leveling (1:05-2:28): It's essential when direct instrument or staff placement is impossible due to obstacles.
Benefits of Reciprocal Leveling (2:49-3:03): This technique helps in eliminating errors related to curvature, refraction, and collimation, providing accurate height differences.
Collimation Error (14:23-15:37): The lecture defines collimation error as an instrumental error where the line of collimation is not horizontal even when the bubble is centered.
Calculating Collimation Error (16:10-19:50): The video explains how to calculate collimation error based on measured and true staff readings, and how to determine the angular error.
Exact Height Difference Calculation (12:19-13:20): The video provides a formula to calculate the exact height difference between two points using readings taken from both ends of the obstruction. This formula is particularly useful for numerical problems in exams.
Consideration of Earth Curvature and Refraction (19:51-21:58): In large survey areas (geodetic surveys), the effects of earth curvature and refraction must be considered, while in small areas (plane surveys), they can be neglected when calculating collimation error

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