Civil Engineering

Sunday, February 15, 2015

Topography,Surveying equipment and Surveying techniques

Topography

Topography may be a field of geoscience and planetary science comprising the study of surface form and options of the planet and alternative evident astronomical objects together with planets, moons, and asteroids. It additionally the outline of such surface shapes and options (especially their depiction in maps).

Types of surveys

Specializations of mensuration is also classed otherwise consistent with the native organization or regulative body, however is also generally sorted as follows.

1. As-built survey: a survey administered throughout or straight off when a construction project for record, completion analysis and payment functions. AN as-built survey is additionally called a 'works as dead survey' and documents the placement of the recently made components that square measure subject to completion analysis. As engineered surveys square measure usually conferred in red or discriminate and overlaid over existing style plans for direct comparison with style data.

ELEVATION (Auto Level)

ELEVATION

The elevation of a geographic location is its height above or below a fixed reference point. Commonly, elevation is measured using the center of the Earth as the reference point.

What is height of instrument (HI)

In any particular set up of an instrument height of instrument, which is the elevation of the line of sight, is constant. The elevation of unknown points can be obtained by subtracting the staff readings at the desired points from the height of instrument. This is the basic behind the height of instrument method for reduction of level.

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