WHAT IS THE ORDNANCE SURVEY MAPPING

 Upendra Kumar  

Ordinance survey is the national mapping agency of Great Britain. The history of the foundation date of the ordnance survey in June 1791. The start of survey work in 1783. One is the most chapter is added in ordnance survey mapping, surveying with the help of theodolite in 1791.

The basis of ordnance surveying mapping was triangulation. Triangulation was the universal name of providing Skelton for control of survey operation. The use of a topographical survey in the ordnance survey map from 1819 and the scale of the map was 1:10560.

For purpose of land and taxes, the scale was used 1:2500 or 1:1250 and a map was drawn for this purpose on a national grid system. The national grid large-scale mapping started in 1944. The scale used for rural area 1:2500 and urban area 1:1250 for map preparation. The digital map available from 1995 on a scale of 1:25000 and 1:10000.

                                               

OLD OS MAP

                                               BASIS OF ORDINANCE SURVEY

The original ordnance survey map was made of a triangulation survey. during the second survey in 1934 required the precise location of triangulation pillars. The location of triangulation pillars is determined by triangulation survey and build the triangulation pillars on a hilltop and it's made of concrete or stone. The modern OS survey based on GPS and AERIAL PHOTOGRAPHIC SURVEY.

The GPS station is known as OS net. OS survey used ordnance survey national grid system with longitude and latitude for location purposes. Ordnance survey also used geographical datum point with geodetic reference.  Four or six digits are used for a grid reference.

In the preparation of the master copy of the OS map following layers should be used.

• Topography Layer
• Green Space Layer
• Highway Network
• Water Network
• Detail Path Network

The following symbols are used in the preparation of the OS survey map.

LEGEND IN OS MAP

     

OS survey map also available on arc gis plateform

GIS MAP

METHOD OF TACHEOMETRIC SURVEY

 Upendra Kumar

                  THERE ARE TWO METHOD OF TACHEOMETRY SURVEY

1. Stadia Method.

2.Tangential Method.

1. Stadia Method-

i. Fixed Hair Method:- This method of tacheometry is most commonly used. In this method, the stadia hair interval is fixed. When a staff is sighted through the telescope, a certain length of the staff is intercepted by the stadia lines and from this value of the staff intercept, the distance from the instrument to the staff station may be determined.

The measurement in tacheometry on fixed hair method has three types.

Case I:-When the line of sight is horizontal and the staff held verticle 

TACHOMETER

O= Optical center of object-glass.

A₁,A₂,C= Reading on the staff.

a₁,a₂ and c₁=Bottom, top and central hair on the diaphragm.

a₁,a₂=i= length of the image.

A₁,A₂= staff intercept.

F= Focus

V= Vertical of the instrument.

f= Focal length of the object-glass.

d= distance between the optical center and the vertical axis of the instrument.

u= Distance between optical center and staff.

v=Distance between optical center and image.

In the triangle a₁Oa₂=A₁OA₂

i/s=v/u                                                                                                     (1)

or v= iu/s

we know that property of lenses

1/v+1/u=1/f                                                                                              (2)

putting the value of v in equation (2)

     or           1/iu/s+1/u=1/f

     or             {1/u{s/i+1}=1/f

      or            u= {s/i+1}f                                                                           (3)

      D=           u+d

      D=          {s/i+1}f +d

      = s/if+f+d

       = f/i*s+(f+d)                                                                                        (4)

Hence ,

Horizontal distance (D) of the staff from the vertical axis of the instrument is given by 

D=f/i*s+(f+d)

Elevation of the staff station

= Elevation of the instrument axis-Axial hair reading

Case II:- When the line of collimation is inclined to the horizontal and the staff is held vertically.

HORIZONTAL METHOD

 Let A=The instrument station

       A'= The position of the instrument axis.

       P=  The staff station.

D, C, B=The points on the staff cut by the hairs of the diaphragm.

CA'K=𝞱=The inclination of the line of collimation A'C to the horizontal.

  DB =S=The staff intercept.

   PC=h=The axial reading.

   A'C=L= The distance along the line of collimation from the instrument axis A' to point C.     

A'K=D= The horizontal distance from the vertical axis of the instrument to the staff station P.

KC=V=The vertical distance from the instrument axis to point C.

   

In the above picture

Draw a line D'B' on the line A'C

The angle 𝛃 is small it may be neglected

From formula (4)

L= f/i D'B'+(f+d)

  = f/i✖S cos𝞱         

Horizontal Distance A'K=D=L cos𝞱 

= f/i✖S cos  ²𝞱 +(f+d) cos𝞱

Vertical distance KC=V=L sin𝞱

V=f/iS sin𝞱cos𝞱+(f+d)sin𝞱

Case II:-When the line of collimation is inclined to the horizontal and the staff is held normal to the line of collimation.

In the above picture.

                     

              A'C= the line of collimation at an angle 𝞱 to the horizontal.

               DB=S= the staff intercept.

                PC=h=the axial reading.

                Draw a line CC1

                 angle CPC1=angle CA'K=𝞱

                 Then CC1=hsin𝞱

                           PC1=PCcosCPC1=hcos𝞱

                             L=f/i*S+(f+d)

       Horizontal distance

                         D=f/i*Scos𝞱+(f+d)cos𝞱+hsin𝞱

                  vertical distance V= L sin𝞱

                                               =f/i Ssin𝞱+(f+d)sin𝞱

       

 2.Tangential Method.  :-       

This method is used when the telescope is not fitted with a stadia diaphragm. The horizontal and vertical distances of the staff station from the instrument station may be computed from observations taken to two vanes or targets on the staff at a known distance(S).

Solve the triangle BA'K and triangle CA'K 

BK=Dtan∝1

CK=Dtan∝2

S=D(tan∝1-tan∝2)

D=S/(tan∝1-tan∝2)

V=Dtan∝2

SEE ALSO:-HOW PREPARE A GIS MAP

WHAT IS TACHEOMETRIC SURVEY

Upendra Kumar

                                              WHAT IS THE TACHEOMETRY SURVEY

A tachometry is a branch of angular measurement in which the horizontal and vertical distances of points are obtained by instrumental observation, chaining being thus entirely eliminated. The accuracy of the tacheometer is less than that of chaining, but it is far more rapid in a rough and difficult country where ordinary leveling is tedious chaining is difficult and slow.

                                  PRINCIPLE OF TECHEOMETRY

The principle of techeometry is based on the property of the isosceles triangle where the ratio of the distance of the base from the apex and the length of the base is always constant.

Here O₁a₁a₂,O₁b₁b₂ and O₁c₁c₂ are the isosceles triangles and its base distance from the apex is D₁, D₂ and D₃. The length of the bases or staff intercept is S₁S₂and S₃.

According to the law of isosceles triangle 

D₁/S₁=D₂ /S₂=D₃/S₃= f/i 

Where f =focal length of the objective and i= stadia intercept

f/i is called the multiplying constant.

                                            THEORY OF THE TACHEOMETRY

O= Optical center of object-glass.

A₁,A₂,C= Reading on the staff.

a₁,a₂ and c₁=Bottom, top and central hair on the diaphragm.

a₁,a₂=i= length of the image.

A₁,A₂= staff intercept.

F= Focus

V= Vertical of the instrument.

f= Focal length of the object-glass.

d= distance between the optical center and the vertical axis of the instrument.

u= Distance between optical center and staff.

v=Distance between optical center and image.

In the triangle a₁Oa₂=A₁OA₂

i/s=v/u                                                                                                     (1)

or v= iu/s

we know that property of lenses

1/v+1/u=1/f                                                                                              (2)

putting the value of v in equation (2)

     or           1/iu/s+1/u=1/f

     or             {1/u{s/i+1}=1/f

      or            u= {s/i+1}f                                                                           (3)

      D=           u+d

      D=          {s/i+1}f +d

      = s/if+f+d

       = {f/i}*s+(f+d)

Where f/i is called multiplying constant and is value for analatic lenses =100

 (f+d) is called additive constant and its value is given by tacheometre manufacture.

                 INSTRUMENT USED IN TACHEOMETRIC SURVEY

There are two types of instruments used in the tachometer survey.

1. Tachometer:- Tacheometer is also a transits theodolite having a stadia telescope. A telescope fitted with a stadia diaphragm is called a stadia telescope. If any telescope equipped with two horizontal hairs called stadia hairs to the regular hairs. The additional hairs are equidistant from the central one and are also known as stadia lines. The types of stadia diaphragm

The telescope used in the tacheometer is in anallatic telescope or telescope fitted with an anallatic lense. The value of constant f/i should be 100.

2. Stadia rod.

Stadia rod is used in tacheometric surveying may be folding and 5 cm to 15 cm wide and 3m to 4m to long. It is graduated in meters, decimeters, and centimeters.

Generally, three kinds of the telescope are used in stadia measurement.

1. The external-focusing telescope:-In the external-focusing telescope the diaphragm is to the outer tube and the objective to the inner tube. By turning the focussing screw the distance between the objective and diaphragm altered to form a real image on the plane of the crosshairs.

2. The internal-focusing telescope:-In the internal focussing telescope, the eyepiece, and objective do not move. A double concave lens is fitted with a rack and pinion arrangement between objective and eyepiece. if the focussing screw is turned a real image is formed on the plane of the cross-hair.

3. The anallatic telescope:-The telescope fitted with anallatic telescope is called anallatic telescope.

THERE IS TWO METHOD OF TACHEOMETRIC SURVEY.

1. Stadia Method.

2. Tangential Method.

MY FORWARD WORK: HOW DOES GPS WORK WITH SATELLITE

MY FORWARD WORK: HOW DOES GPS WORK WITH SATELLITE: Upendra Kumar In this article here two words are used first is GPS and the second is SATELLITE, first, we know what is satellite.           ...

HOW DOES GPS WORK WITH SATELLITE

Upendra Kumar

In this article here two words are used first is GPS and the second is SATELLITE, first, we know what is satellite.  

                                       What is Satellite

A satellite is an object in space that orbits or circles around a bigger object. There are two kinds of satellites: natural satellite and artificial satellite.

1. Natural Satellite.:- In space, about 53 satellites but the big example of the natural satellites is earth and moon. The earth is orbiting the sun and the moon is orbiting the earth.

           

NATURAL SATELLITE IMAGE

2. Artificial Satellite:-An artificial satellite is an object that is made by man and launched by using rockets. There are currently over a thousand active satellites orbiting the Earth. The size, altitude, and design of a satellite depend on its purpose.

GPS SATELLITE

GPS Satellite also an artificial satellite, GPS satellite is used for satellite navigation and give autonomous geo-spatial positioning. The GPS satellite consists of electronic receivers to determine their location with longitude, latitude, and altitude with high precision using time signals. Minimum four satellites required for receiving the three-position coordinates and clock deviation from the satellite time. Each GPS satellite is continuously transmitting the radio signals containing the current time and data about its position. the speed of radio waves is constant and independent of the satellite speed, the time delay between when the satellite transmits a signal and the receiver receives it is proportional to the distance from the satellite to the receiver. A GPS receiver monitors multiple satellites and solves equations to determine the precise position of the receiver and its deviation from true time.

                                          HOW DOES  GPS  WORK WITH SATELLITE

There are three segments required with working GPS with the satellite.
1. Space Segment.
2. Control Segment.
3. User Segment

1. The space segment contains 24 satellites in 12 hours, near-circular orbits at an altitude of about 20000 with an inclination of orbit 55°.At least 4 sett elite views on the earth's surface in 3d mode.
2. Control Segment:- It consists of three-part
A. Master Control Station
B. Monitor Status
C. Upload Status.
3. User segment:- User segment contains an antenna, receiver, a data processor with software, and a control/ display unit. GPS receiver measures the range, phase, and other data using navigation signals minimum satellites and computes 3D position, velocity, and system time.

GPS SEGMENT

What Is The Method Of Plane Table Survey

Upendra Kumar

There are four methods of surveying with the plane table.

1. Radiation: It is used for locating the details from stations, which have been previously established by other methods of surveying such as triangulation or transit type traversing.

 

Radiation Method Of Plane Table

In this method, the point is located on the plan by drawing a ray from the plane table station to the point, and plotting to the scale along the ray the distance measured from the station to the point. The method is suitable for the survey of the small areas which can be commanded from a single station.

Procedure:

>Select a point P so that all points to be located are visible from it.

>Set up the table at P and after leveling it, clamp the board.

> Select a point p on the sheet so that it is exactly over the station P on the ground by the use of a U frame. The point represents on the sheet the instruments station P on the ground.

> Mark the direction of the magnetic meridian with the help of the compass in the top corner of the sheet.

>Centring the alidade on p, sight the various points, A, B, C, etc, and draw rays along the fiducial edge of the alidade lightly with a chisel pointed pencil.

>Measure the distances PA, AB, AC, etc, from P to the various points with the chain or tape, or by stadia and plot them to scale along the corresponding rays. Join the points a,b,c, etc, to give the outline of the survey.

NOTE:- The fieldwork can be checked by measuring the distances, AB, BC, CD, etc,

2. INTERSECTION: In this method, the point is fixed on the plan by the intersection of the rays drawn from the two instruments station. The line joining these stations is called the baseline.

Intersection Method Of Plane Table

Procedure:- 

i.  select two points P and Q  on the ground so that visible each other. 

ii. Set the table at  P and level and mark the magnetic north on the paper with the help of a compass.

iii. Alidade kept on p sight the objects Q, A, B, C, D, E, and F  and draws the rays along the fiducial edge of the alidade towards Q, A, B, C, D, E, F.

iv. Measure the Pand Q and mark the point q with a suitable scale on the paper along the line drawn pq.

v. Shift the table on Q and center the table so that q is exactly over Q. Orient the table by backsighting P and clamp the table.

vi. With the alidade touching q.sight the same object and draws rays.The intersection of determining the position of A, B, C, etc.

3.Traversing method:-This method is similar to the closed traverse method. It is used for locating the details between the stations which is fixed by another method of surveying. This method is also used in a topographical survey. 

TRAVERSING METHOD OF PLANE TABLE

Procedure:-

i. Set the plane table at station A. Make the center and level then board clamped.

ii. Mark the magnetic meridian on the sheet.

III. Centre the alidade on point a sight the station B and measure the length of AB and draw the rays on a suitable scale on the sheet ab with the edge of alidade.

iv. Locate the details by the use of the radiation method or offset method.

v.Set the plane table on station B. Orient the table and backsight to A then sight the station C.

Measure the length BtoC and draw the line bc on a previous use scale.

vi. Continue the process until all the remaining stations are plotted.

vii. It can be also checked from the sighting stations or A to C and B to D or B to E.

4. Resection Method.

This method is used for establishing the instrument stations or after completing the traverse surveying the important object cannot be located due to difficulties and missed the station.

PROCESS:-

i.Select the two stations P and Q on the ground and measure the length PQ and plot to a scale pq on a suitable scale.

ii. Set the table at P , Centre, and level the table so that the point p is over the P.

iii. Place the alidade along pq, orient the table by turning the board until the signal at Q is bisected, and then clamp it.

iv. With the alidade touching at p sight the station R and draw a ray p to r.

v. Shift the table at R. and make the center and level and sight the point P by back sighting and clamp the table.

vi.  With the alidade centered on q, sight the station Q and draw a ray. The point of intersection of this ray and that previously drawn from p gives the required point r.

     

See ALso

WHAT IS THE PLANE TABLE SURVEY

What is the principle and procedure of chain surveying

What is the principle and uses of remote sensing

Height measurement by use transit theodolite

 upendra kumar

Instrumental method:-

>PROCESS:- Set the theodolite at O, leveled the instrument used plate level and altitude level.   Measured the distance QR with the chain or tape. The angle of elevation A and angle of depression B also measure. Let the distance OR = D. Then use the tan formula.

h2 = D* TAN A

h3=D*TAN B

Total height of the PR : h2+h3

RL OF P= BM+h1+h2

RL OF Q= BM+h1-h2

 In the nowadays height of an object also determined by the use of TOTAL STATION, DRONE SURVEY, etc.

See also- TECHNO UPENDRA

HOW TO SET DIMENSION STYLE SETTING

how to measure excavated material from mines

 Upendra Kumar

                                            INTRODUCTION

The purpose of the measurement of excavated material in the mines is a calculated quantity of excavated material. The process of excavation of the underground and opencast is different, Then the method of measurement of also different. In underground mining, the measurement of excavation is done by after the mining out the mineral, but in the open cast, the measurement work starts before the start of the mining.

                   The work should be done before starting mining.

1.In In the virgin area of the quarry construct the masonry pillars at 30 mt of the interval. All pillars will be constructed in the virgin area of the quarry where pillars are not disturbed when the mining operation is running. The pillars are so constructed that when they are joined in one direction. A series of parallel lines are formed in the general direction of the proposed face. A baseline is made on the masonry pillars. write the number on masonry pillars. Takecoordinate and also take a reduced level of every pillar. Another masonry pillars are constructed at a right angle to a series of pillars are constructed first time on the virgin area.

MASONRY PILLARS

 These two lines are called the reference line. which should be utilized for drawn 15 mt grid lines which is parallel to reference lines on both sides. Before start, the mining operation surveyor carries out an initial survey and level work on 15 mt intervals with the help of Theodolite, total station, or the auto level.

Thereafter every month survey and level carry out of the excavated area for making a new profile of the quarry.

If required separate volume of the strata or volume of soil take the RL before drilling and blasting started.

For stone take the RL of coal top and for coal take the RL floor of the coal seam.

First, calculate the total excavation volume.

Total excavation= R.L OF OGL- RL OF Coal floor

The volume of soil     = R.L of ogl- stone top.

The volume of stone = R.L of stone top- R.L of coal top.

The volume of coal = R.L of coal top - R.L of coal floor.

Plot the grid on a small scale map and write the RL of different strata of a different color and finally calculate the section-wise area on the 15 mt grid.https://www.technoupendra.com/2020/04/how-to-calculate-area-in-map.html

 Calculate the volume by trapezoidal rule or any other suitable rule or software.
  

How to measure excavated material from mines

How to measure excavated material from mines

 Upendra Kumar

                                            INTRODUCTION

The purpose of the measurement of excavated material in the mines is a calculated quantity of excavated material. The process of excavation of the underground and opencast is different, Then the method of measurement of also different. In underground mining, the measurement of excavation is done by after the mining out the mineral, but in the open cast, the measurement work starts before the start of the mining.

                   The work should be done before starting mining.

1.In In the virgin area of the quarry construct the masonry pillars at 30 mt of the interval. All pillars will be constructed in the virgin area of the quarry where pillars are not disturbed when the mining operation is running. The pillars are so constructed that when they are joined in one direction. A series of parallel lines are formed in the general direction of the proposed face. A baseline is made on the masonry pillars. write the number on masonry pillars. Takecoordinate and also take a reduced level of every pillar. Another masonry pillars are constructed at a right angle to a series of pillars are constructed first time on the virgin area.

MASONRY PILLARS

 These two lines are called the reference line. which should be utilized for drawn 15 mt grid lines which is parallel to reference lines on both sides. Before start, the mining operation surveyor carries out an initial survey and level work on 15 mt intervals with the help of Theodolite, total station, or the auto level.

Thereafter every month survey and level carry out of the excavated area for making a new profile of the quarry.

If required separate volume of the strata or volume of soil take the RL before drilling and blasting started.

For stone take the RL of coal top and for coal take the RL floor of the coal seam.

First, calculate the total excavation volume.

Total excavation= R.L OF OGL- RL OF Coal floor

The volume of soil     = R.L of ogl- stone top.

The volume of stone = R.L of stone top- R.L of coal top.

The volume of coal = R.L of coal top - R.L of coal floor.

Plot the grid on a small scale map and write the RL of different strata of a different color and finally calculate the section-wise area on the 15 mt grid.https://www.technoupendra.com/2020/04/how-to-calculate-area-in-map.html

 Calculate the volume by trapezoidal rule or any other suitable rule or software.
  

How to measure excavated material from mines

 Upendra Kumar

                                            INTRODUCTION

The purpose of the measurement of excavated material in the mines is a calculated quantity of excavated material. The process of excavation of the underground and opencast is different, Then the method of measurement of also different. In underground mining, the measurement of excavation is done by after the mining out the mineral, but in the open cast, the measurement work starts before the start of the mining.

                   The work should be done before starting mining.

1.In In the virgin area of the quarry construct the masonry pillars at 30 mt of the interval. All pillars will be constructed in the virgin area of the quarry where pillars are not disturbed when the mining operation is running. The pillars are so constructed that when they are joined in one direction. A series of parallel lines are formed in the general direction of the proposed face. A baseline is made on the masonry pillars. write the number on masonry pillars. Takecoordinate and also take a reduced level of every pillar. Another masonry pillars are constructed at a right angle to a series of pillars are constructed first time on the virgin area.

MASONRY PILLARS

 These two lines are called the reference line. which should be utilized for drawn 15 mt grid lines which is parallel to reference lines on both sides. Before start, the mining operation surveyor carries out an initial survey and level work on 15 mt intervals with the help of Theodolite, total station, or the auto level.

Thereafter every month survey and level carry out of the excavated area for making a new profile of the quarry.

If required separate volume of the strata or volume of soil take the RL before drilling and blasting started.

For stone take the RL of coal top and for coal take the RL floor of the coal seam.

First, calculate the total excavation volume.

Total excavation= R.L OF OGL- RL OF Coal floor

The volume of soil     = R.L of ogl- stone top.

The volume of stone = R.L of stone top- R.L of coal top.

The volume of coal = R.L of coal top - R.L of coal floor.

Plot the grid on a small scale map and write the RL of different strata of a different color and finally calculate the section-wise area on the 15 mt grid.https://www.technoupendra.com/2020/04/how-to-calculate-area-in-map.html

 Calculate the volume by trapezoidal rule or any other suitable rule or software.