Leveling

Leveling : is the procedure used to determine difference in elevation between points that are some distance from each other

General Terms Elevation: is a vertical distance above or below reference datum Level line: is a line in level surface, a level surface is a curved surface. Mean sea level: reference datum that is universally employed in surveying studies

Leveling Concepts

Types of Surveying Levels Automatic Digital Tilting Dumpy Rotary Laser

Engineers’ Automatic Level

Definitions for differential levelling Bench Mark (BM): is a permanent point of known elevation ( published) Temporary Bench Mark: (TBM): is semi permanent point on known elevation. (nails in the rod of trees, not publish) Turning Point (TP): is a point temporarily used to transfer an elevation. Back sight: is a rod reading taken on a point of known elevation. Height of Instrument (HI): is the line of sight through the level. HI= Elev. BM + BS

Foresight (FS):is a rod reading taken on TP, BM , TBM to determine its elevation. HI-FS= Elev. of TP(or BM or TBM) Intermediate Sight (IS): is a rod reading taken in any other point where the elevation is required. HI-IS=Elev.

Leveling Procedure – One Setup

Leveling Procedure – One Setup

Leveling Procedure – One Setup

Leveling Procedure – Multiple Setups

Ex 1: complete accompanying set of differential leveling and perform the arithmetic check. Station BS (m) HI (m) FS (m) Elevation (m) BM3 1.613 133.005 TP1 1.425 1.927 TP2 1.307 1.710 TP3 1.340 1.273 0.780

Ex 2: complete accompanying set of differential leveling and perform the arithmetic check. Station BS FS Elevation BM7 4.368   82.206 TP1 6.907 4.538 TP2 4.680 8.800 TP3 3.730 5.978 TP4 8.464 5.245 3.598