adsense analytic

Showing posts with label Land Survey. Show all posts
Showing posts with label Land Survey. Show all posts

Wednesday, February 13, 2019

Principles of chain surveying

Chain survey belongs to the easiest method of surveying. Under this type of survey, only measurements are captured in the construction site, and the other works, like plotting measurement etc. are carried out in the office. Irrespective of angular measurements, only linear measurements are undertaken. It is mostly effective for small plane areas having very few details. If it is performed efficiently, it provides quite perfect results.

To conduct this survey, the following items are required in job site - Chain, Tape, Ranging-Rod, Arrows, Cross staff

Relevance of Chain Survey - Chain survey can be undertaken for the following purposes:

1. The area required to conduct survey is relatively small
2. The ground is level to some extent
3. The area is open and
4. Details to be gathered are simple and less.


Survey Station - Survey stations are categorized as follow : Main Stations, Subsidiary or tie

Main Stations: Main stations refer to the end of the lines, which manage the boundaries of the survey, and the lines which attach the main stations remind of the main survey line or the chain lines.

Subsidiary or the tie stations: Subsidiary or the tie stations belong to the points chosen on the main survey lines, where it is important to trace the interior detail like fences, hedges, building etc.

Tie or subsidiary lines: A tie line connects two fixed points on the main survey lines. It facilitates to verify the exactness of surveying as well as trace the interior details. The location of each tie line should be adjacent to some features, like paths, building etc.

Base Lines: It is the primary and longest line, which moves roughly through the center of the field. All the other measurements to demonstrate the details of the work are obtained relating to this line.

Check Line: A check-line also called as proof-line belongs to a line that attaches the apex of a triangle to some fixed points on any two sides of a triangle. A check-line is calculated to verify the exactness of the framework. The length of a checking line, as calculated on the ground should satisfy its length on the plan.

Offsets: Offsets stand for the lateral measurements from the baseline to secure the positions of the several objects of the work in relation to the baseline. These are normally set at right angle offsets. It is also drawn by applying a tape.

Chain survey method:
1. Reconnaissance: The initial examination of the area prepared for survey is known as reconnaissance. The surveyor examines the area to be surveyed as well as arranges index sketch or key plan.
2. Marking Station: Surveyor settles the required no of stations at areas from where maximum possible stations can be arranged.


The marking is done with the following processes:

a. Setting ranging poles
b. Pushing pegs
c. Marking a cross if the ground is solid
d. Digging and setting a stone.


3. After that, the surveyor chooses the way for transforming the main line, that should be horizontal and dirt free as possible and should move around through the center of work.
4. Then ranging roads are secured on the stations.
5. As soon as the stations are fixed, chaining should be done.
6. Create ranging wherever required.
7. Work out the change and offset.
8. Enter in the field the book.


Principles of chain surveying

Read Continue
~~~~~~~~~~~~~~~~~~~~~~~~
Published By
Rajib Dey
www.constructioncost.co
~~~~~~~~~~~~~~~~~~~~~~~~

Saturday, November 3, 2018

How to measure the land area for irregular & large land tracts

Various types of surveying methods are used for conducting survey of irregular and large land tracts. Some methods are easily understandable and based on elementary geometry, others are complicated and may contain GPS and satellite imagery.

In this article, useful information is given on various options and technologies accessible to the surveyor.

The calculation should be done for Land for different purposes like prior to purchase, while performing stock taking, erecting a boundary wall, controversy with a neighbor over demarcation, etc. Making calculation for regular land area is simple since they contain mostly rectangle or other geometrical shapes. Recalling geometry studied in High School we can do the measurements and arrive at the results. But, the process becomes difficult for measurement, if the area of land is extremely irregularly shaped or large tracts of land are purchased like a farm measuring miles across.

In this article, you will be familiar with some self-reliant methods of calculating your land and some high technology solutions.

Given below, some useful methods for measuring the land with simple geometry, maps and planimeter, GPS, Aerial photography, Satellite imagery, Google earth, maps and graphs, measuring wheels.

Geometric Method: Under this method the odd shaped plot is surveyed and plotted over graph paper. The area of the plot is then subdivided into geometric figures and the areas of these figures are measured with formulae.

Initially, the greater size geomatric figure that can be perfectly drawn in the map is created and after that smaller shapes are produced unless the complete space is captured more or less.

Once the computation for areas of these figures is done, then these are added to determine the total area.

As for instance:
Area of Rectangle: Length x Breadth
Area of Square: Length x Length
Area of Triangle: 0.5 x Base x Height
Area of Trapezium: 0.5 x (Length 1 + Length 2) x Height
The above formulas are used to find out the exact area.


Planimeter on Map: Planimeter is a small gadget that is utilized for working out the areas of a graphically represented planar region. The planimeter can calculate all regular and irregular shapes. It is required to pivot it at any point and then run the end pin all over the perimeter of the area to be calculated. It contains a compliant linkage that facilitates it to move devoid of any effort in all directions.

How to measure the land area for irregular & large land tracts

Read more

~~~~~~~~~~~~~~~~~~~~~~~~
Published By
Rajib Dey
www.constructioncost.co
~~~~~~~~~~~~~~~~~~~~~~~~

Friday, May 25, 2018

Basic differences among Prismatic Compass and Surveyors Compass

Compass belongs to an instrument that plays an important role to workout the direction of a survey line relative to magnetic north-south.
The magnetic north-south direction is treated as the reference direction and it is known as meridian (reference direction) and the angle among the line and the meridian is known as bearing. The compass is applied for calculating the direction of a line to simplify the surveying process significantly.
The variations among prismatic and surveyor’s compass are given below :-
Prismatic Compass
1. Graduation circle is attached to a broad type needle. Therefore, it will not revolve with the line of sight.
2. A prism is situated at viewing end.
3. Sighting and reading are performed concurrently.
4. The magnetic needle does not perform like an index.
5. The graduations are in whole circle bearing.
6. Graduations are pointed inverted as its reflection is examined via prism.
7. The reading is captured through a prism.
8. Tripod may or may not be applied. It can be persisted with a stretched hand also.
Surveyors Compass
1. Graduation circle is attached to the box. Si, it revolves with the line of sight.
2. No prism exists at viewing end except for a slit.
3. It is not possible to perform sighting and viewing all together.
4. Magnetic needle functions as index at the time of reading.
5. The graduations remain in quadrantal system.
6. Graduations are pointed directly. They are not inverted.
7. The reading is captured by directly viewing from top glass.
8. Tripod is necessary for being applied.
Basic differences among Prismatic Compass and Surveyors Compass

~~~~~~~~~~~~~~~~~~~~~~~~
Published By
Rajib Dey
www.constructioncost.co
~~~~~~~~~~~~~~~~~~~~~~~~