Describe in brief profile levelling.

Describe in brief profile levelling.
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1 Answer

Answer :

The operation of taking levels along the center line of any alignment at regular interval is called longitudinal or profile levelling.

Along the alignment, spots are marked at regular interval along with the apex points where the alignment changes the direction.

Setting the level midway between ends of stretch of road which can be controlled from one point and spot levels are taken on the points on the center line of the alignment.

The staff readings and chainage of the points are noted in the field book.

The RLs of all the points are calculated and the elevations of all the points are plotted against their chainage to obtain ground profile along the alignment.

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Explain the procedure of profile leveling for construction of road.

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Describe method of measuring distances on ground using chain and arrows.

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Describe instrumental errors in leveling.

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Profile levelling is usually done for determining (A) Contours of an area (B) Capacity of a reservoir (C) Elevations along a straight line (D) Boundaries of property

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Explain the procedure for profile levelling and cross Sectioning

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Define the following terms: i) Level line ii) Bench Mark iii) Change point iv) Profile levelling

Description : Define the following terms: i) Level line ii) Bench Mark iii) Change point iv) Profile levelling

Last Answer : i) Level line - It is line lying in a level surface; it is therefore, normal to the plumb line at all points. ii) Bench Mark - These are fixed points or marks of known RL determined with ... the centerline of a proposed ditch or road or the centerline of a natural feature such as a stream bed.

What is changing face

Description : As used in survey

Last Answer : It's the operation of changing the face of telescope from left to right and vice versa.

The process of surveying is therefore in three stages namely:

Description : The process of surveying is therefore in three stages namely:

Last Answer : (i) Taking a general view This part of the definition is important as it indicates the need to obtain an overall picture of what is required before any type of survey work is undertaken. In ... of quantities, datasheets, drawings and in land surveying maps and plan showing the features on the land.

Tacheometric Surveying

Description : Tacheometric Surveying

Last Answer : Tacheometric is a branch of surveying in which horizontal and vertical distances are determined by taking angular observation with an instrument known as a tachometer. Tacheometric surveying is adopted in rough ... be prepared for investigation works within a short time on the basis of such survey.

Explain the temporary adjustments of prismatic compass.

Description : Explain the temporary adjustments of prismatic compass.

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State the fundamental axes and mention their relationship for a dumpy level.

Description : State the fundamental axes and mention their relationship for a dumpy level.

Last Answer : Fundamental axis of dumpy level are as follows; i) The vertical axis ii) The axis of bubble tube iii) The line of collimation iv) The axis of the telescope Relationship between ... iii) Axis of telescope and line of collimation should coincide when dumpy level is correctly leveled.

What consideration would you have while selecting survey stations and survey lines in a chain survey?

Description : What consideration would you have while selecting survey stations and survey lines in a chain survey?

Last Answer : Following points to be considered while selecting survey stations and survey lines 1) Main survey station should be mutually visible. 2) All triangles should be well conditioned. 3) The survey line should lie ... of the area so as to form the frame work of triangles on it to cover maximum area. 

What are offsets? How are they taken and recorded? Explain with sketch.

Description : What are offsets? How are they taken and recorded? Explain with sketch.

Last Answer : Offsets are lateral measurement to the base line. They are Located by judgment if short And by instruments (optical square or cross staff) if long and measured by metallic tape and shown with their chainages on base line

Define : 1) Bench mark 2) Datum surface 3) Line of collimation 4) Change Point

Description : Define : 1) Bench mark 2) Datum surface 3) Line of collimation 4) Change Point 

Last Answer : 1) Bench mark: - It is a fixed reference point of known elevation.. 2)Datum surface :-It is any arbitrarily assumed level surface from which vertical distance are measured 3) Line of collimation:- ... which the fore and back sights are taken.  It is the point denoting the shifting of the level.

State the situation where plane table is suitable.

Description : State the situation where plane table is suitable. 

Last Answer : 1) It is most suitable for preparing small scale maps 2) It is suitable in magnetic are where compass survey is not reliable 3) It is most suitable for filling in details between stations fixed by triangulation 4) It is suitable where accuracy is not required.

How would you detect presence of local attraction at a place ?

Description : How would you detect presence of local attraction at a place ?

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Define: WCB and Quadrantal Bearing system

Description : Define: WCB and Quadrantal Bearing system

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State the two uses of survey based on geodetic surveying

Description : State the two uses of survey based on geodetic surveying

Last Answer : Two uses of survey based on geodetic surveying:- i) To determine the precise position s on the surface of the earth. ii) Preparation of maps of large area like map of a country, state ... ) Establishment of GTS bench Marks across the country. iv) Preparation of military maps for defense purposes.

Write errors in leveling and corresponding precaution

Description : Write errors in leveling and corresponding precaution

Last Answer : i) Instrument error with respect to bubble tube, leveling staff. 1.If bubble tube is sluggish it may apparently be in the center though the bubble line is not horizontal. Precaution - ... reading. Precaution- Leveling should be properly done by bringing the bubble of bubble tube at Centre.

State the important points kept in mind while recording the staff readings in level pages with respect first reading, intermediate reading, last reading, change point, carry forward from one page to next page-Remark

Description : State the important points kept in mind while recording the staff readings in level pages with respect first reading, intermediate reading, last reading, change point, carry forward from one page to next page-Remark

Last Answer : 1) First reading is on bench mark point and should be noted in back sight(BS) column 2) Intermediate reading (IS) should be taken on the points between first and last station. 3) Last reading ... column of next page 6) Remark column should have denote First and Last RL along with change points.

Draw a sketch and explain how to find height of chajja or slab using dumpy level.

Description : Draw a sketch and explain how to find height of chajja or slab using dumpy level.

Last Answer : Explanation : 1. First the back sight reading is taken on floor level whose RL is known to us; from which RL of instrument axis can be find out by adding RL of BM and BS reading. 2. Now ... staff reading. 4. Finally height of chajja is calculated as RL of slab bottom -  RL of floor top.