Showing posts with label Surveying Sciences. Show all posts
Showing posts with label Surveying Sciences. Show all posts

Basic Methods of Surveying Sciences -CHAIN SURVEYING

1.Only linear measurements are made in the field

2.The principle is the provisions of a frame work of triangles, which could be plotted to scale

3.The lengths of the sides of triangles have to be measured

1.Generally the boundaries of the land parcel are not straight

2.  The land parcel to be surveyed is irregular in shape

3.  The entire area is broken up into a framework of triangles   (ABC & ABD)

4.  The line AB is taken right across the block, which is called   the base on which all other triangles are build up

5.  In addition 2 lines EF and EG (point E on the base is not   necessarily same for 2 lines) are measured for checking

6.  These check lines do not give any additional information

7.  Sometimes they can be used to pickup internal details

8.  Detail is surveyed by rectangular offsets

  Unsuitable for large areas or difficult country
•  Quite well adapted for small surveys on   open   ground with simple details

There are 02 main work
  Field Work  (FW)
  Plan Work   (PW)

Field Work (FW)
•  Reconnaissance
• Examine the area
•Positions of stations are selected and marked. Inter-visibility can be checked using ranging poles
•A sketch of the land showing the arrangement of lines and the numbering or lettering of the stations must be prepared
  Selecting Stations (The following requirement must be fulfilled)
•Survey lines should be as few as practicable, and such that the framework can be plotted
•Normally baseline should be run middle of the area. Triangles are build up on the base
•The triangles should be well conditioned
•Each triangle must have a check line
•As few lines as possible should have to be run without offsets
•Offsets should be short for locating important features

•Selecting Stations (The following requirement must be fulfilled)

•Obstacles for ranging and chaining should be avoided as far as possible
•Lines should be lie over the more level ground

NOTE:  Care should be taken when working   along the road

•Marking Stations

•Wooden Pickets (WP) may be used
•Cement Pickets (CP) can be used when more durability is required

•Running Survey Lines & Survey of Details
•The routine of running a survey line comprises of the chaining of the line & location of the adjacent detail
•Offsets will be taken by estimating the perpendicularity by eye & reads out the lengths of the offsets and chainages
•Also the chainages along the chain line at which boundaries (fence, stream, etc.) are intersected by the chain line should be noted
Field Book Keeping
•There are many regulations for Field Book keeping and you must follow all the regulations
•If not appropriate actions will be taken
•Please go through all the regulations

Plan Work (PW)

•Pencils of 3H or 4H should be used
•Scale must be decided (Indeed this must be decided before proceeding to the field, because the accuracy & precision, which the data to be collected in the field accordingly)
•Other items to be used for plan work are Plotting Scale, Offset Scale, Parallel Ruler, and A3 size Plan Sheet (Quarter Field Sheet) and Drawing Pen for inking

Basic Requirements of Maps
•Dimensioned (or scaled)
•Use of Standard Symbols
•Scale is the relationship between size on the map and size on the ground
–Once centimetre on the map equals 100 metres on the ground, 1:10,000
•A bar scale represents this graphically
–Necessary as plans can be enlarged easily
•A good reference can be found here:

•When plotted there MUST be 2 scale notations:

–The natural scale, 1:100
–A bar scale


•Although it is not necessary to ‘frame’ a plan, it is essential to include other information like:
–Sheet number…

•See the Specimen plan in notice board

•There needs to be a north arrow

–There may also be a grid showing regular intervals of the coordinate system

•The North datum needs to be noted
Lettering, Significant Figures
•There are requirements for particular letter sizes depending on the:
–Scale of the plan
–Importance of the feature
–Legal requirement

•For large scale plans (like we are making), there are recommended significant figures for height and coordinate display

Surveying Sciences -Levelling


1.Purposes of Levelling
2.Levelling Equipment
3.Permanent Adjustment of a Level
4.Some Definitions (Key Words)
5.Reading a staff
6.Level between Two Points
7.Booking and reduction

Find download link of this presentation from the bottom of this post. 

 Click to download this ppt .