How to do Triangulation Survey

By: Haseeb Jamal /HOW TO, NOTES

Triangulation work is carried out in following step.

1. Reconnaissance
2. Erection of Signals & Towers
3. Measurement of Horizontal Angles
4. Astronomical Observations Necessary to Determine the True Meridian and the Absolute Positions of the Stations
5. Measurement of Baseline
6. Adjustment of observed Angles
7. Computations of Lengths of each side of each 
8. Computations of the Latitude and Longitude of ST

1. Reconnaissance:

In geodetic Surveying, reconnaissance consists of: (See also: Reconnaissance in Transportation & Highway Engineering )

1. Examination of the country to be surveyed.
2. Selection of most favorable sides for base lines
3. Selection of suitable positions of  station
4. Determination of indivisibility of station

2. Selection of Station:

The selection of station is based upon the following consideration.

1. The stations should be clearly visible from each other. For this purpose highest commanding positions such as top of hills or mountains is selected.
2. They should form well shaped triangles
3. They should be easily accessible
4. They should be useful for detail survey
5. Thy should be so fixed that the length of sight is not too short or too long

3. Inter-visibility and Heights of Stations:

For indivisibility of two stations they should be fixed on highest available ground. Such as mountain peaks rides or top of hills when the distance b/t the two stations is great and the difference in elevation b/t them is small then it is necessary to raise both the instrument and signal to overcome the curvature of the earth and to clear all the intervening obstruction.
The height of both the instrument and signal above the ground depends upon.

1. Distance between the stations.
2. Relative elevations of stations.
3. The profile of intervening ground.

3. 1. Distance between stations:

If the intervening ground is free any obstruction, the distance of a visible horizon form a station of known elves above datum as well as the elves of the signal while may be just visible at a given distance can be determine from the formula. 

Where

H = ht. of station above a datum

D = Dist from the station to point of tangent

R = mean radius of earth

M = co-efficient of refraction (0.07 for sight over land and 0.08 for sights over water)

D1 and R being expressed in same units. Alternatively, if ‘h’ is in meter and D1 is in kilometer then

H (m) = 0.0673 D12 (km) ==> (A)

Or

H (ft) = 0.574 D1 (miles) ==> (B)

D1 and D2 can be determined and dist b/t two stations will be (D1+ D2)

3. 2. Relative elevations of stations:

A and B are the two stations

D = dist b/t A and B in km
Ha = known elev of ‘A’ above a datum
H = required elev of ‘B’ above a datum
D1 = distance (km) of ‘A’ from pt of tangency (p)
D2 = distance (km) of ‘B’

Dist D1 can be calculated. Hence the required elev, h = 0.0673 D2

Ha = 0.0673 D12 or h = 0.0574 D22 (miles)

 Or 

Now D2 = D - D1

Height or signal / Tower/ scaffold a B = Elev of datum + h - R.L of st B elev of line sight

NOTE:

The line of sight should not be near the surface of ground at pt of tangency on account of strata of disturbed air and should be kept at least 2m (61) above the ground preferably 3m (1D) and this allowance (clearance) should be made in deterring the heights of stations.

3. 3. Profile of intervening ground:

If the peaks in the intervening ground are likely to obstruct, the line of sight, their elevations and locations must be determined.

Procedure:

The elevation of line of sights at the respective points can be computed and the results compared with the ground elevation at those points to determine weather the line of sight clears all the intervening obstruction.

What is Phototheodolite and Applications of a Photo theodolite

By: Haseeb Jamal NOTES, SURVEYING EQUIPMENT

 

 

A photo theodolite is a form of ground camera. It is a combination of camera and theodolite and is used for taking photographs and measuring the angles which the rival plane of collimation makes with base line. Both the theodolite and the camera rotate about a common vertical axis. The instrument is used for terrestrial photogrammetry

It should be noted that the pointing of the theodolite is completely independent of that of the camera, but the horizontal circle, which is located on the top of the camera housing, is fixed in such a way that when the circle reading is zero, the optical axes of the theodolite and camera lie in the same vertical plane. This means that all horizontal directions observed with the theodolite can be easily related to the principal point of the photograph.

Applications of Phototheodolite

Not only is the terrestrial camera useful for mapping construction sites at scales as large as 5 ft. to 1 in., but the photographs can be utilised in a suitable instrument for taking off quantities for earthworks or stock-piles and for directly plotting tunnel profiles and other varied uses. At the other extreme the photo-theodolite can be employed for mapping at small scales and even for extending control.

The Future Role of Geoinformation

The Future Role of

Geoinformation

I recently attended a seminar on the application of 3D, virtual reality (VR) and augmented reality (AR) for local authorities in The Netherlands. A couple of years ago, VR and AR were announced to much fanfare as the next big thing that would revolutionise the surveying profession. But not much has actually happened since then. Well, maybe I am exaggerating a little, but the proclaimed transformation to an immersive or interactive environment has not taken place on such a scale as to send massive shock waves through the geospatial industry. However, the event I attended highlighted a surprisingly large number of applications for implementing these technologies – and not just for the sake of being a front runner and

demonstrating how slickly your organisation has entered the modern era.

Instead, 3D and VR/AR techniques are being used to inform citizens about the impact of the installation of new wind turbines, for example. 3D modelling is already widely used by geomatics professionals, of course. However, it is now increasingly becoming a tool used by local governments too. Obviously, 3D models are very suitable for visualising development plans,

and they help to involve citizens in the planning process. How will the direct vicinity – their local neighbourhood – look after it has undergone major restructuring? 3D models, AR and VR offer tremendous possibilities for smoothing this process in completely new and innovative ways. Participatory spatial planning has only just begun! And with smart cities as one of the

key topics in the geospatial debate, it seems like everything is falling into place at the right time.

VR and AR are important elements to support the implementation of the smart city concept. All of this requires huge volumes of data, so superfast mobile internet is absolutely crucial. 5G will bring the solution, as it will interconnect and control machines, objects and devices in a fast and smart way. Combining 5G with 3D, VR and AR will catapult the smart city concept

so that these technologies will finally deliver on their promises. And as for geomatics, a smart city won’t be smart without it!

https://www.gim-international.com/content/blog/the-future-role-of-geoinformation

What is a Deed of Assignment and the Foolish Risk your taking for not having a Deed of Assignment for your Land

What is a Deed of Assignment?

I took my time to research more concerning deed of assignment, After much research i came across this from omonile lawyers, i bet you majority of land buyers today don't collect this documents after purchasing plot(s) of land.

A deed of Assignment is one of the most important documents YOU MUST HAVE when you conclude a Land Transaction. In fact it baffles me that 6 out of 10 people I know who have bought lands in the past have no deed of assignment. They are always the first to complain that Omonile has defrauded them but they have no proof to show the property has been sold to them other than a receipt.

It’s funny that everyone has the title documents to their car showing who the seller was and how it was transferred from the Seller of that car to you the new owner but when it comes to landed properties which are 10 times more valuable than cars, we fail to ask for this one simple important document that can prove ownership of that land. What then is this all important deed of Assignment I am alluding to? This can be found from the following definitions below:

A deed of Assignment is an Agreement between the Seller of a Land or Property and a Buyer of that Land or property showing evidence that the Seller has transferred all his rights, his title, his interest and ownership of that land to that the Seller that has just bought land.

The Deed of Assignment acts a main document between the buyer and seller to show proof of ownership in favour of the seller. The person or Seller who transfers his rights or interests in that property is usually called the Assignor and the person who receives such right or interest from the Seller is called the Assignee.

A Deed of Assignment therefore is an Agreement where an assignor states his promise that from the date of the assignment or any date stipulated therein, the assignor assigns his ownership in that Land to the assignee. The deed contains very pertinent information for a real estate transaction. For one, it spells out the date when the ownership of the property transfers from one owner to the other. The deed also gives a specific description of the property that is included in the transfer of ownership.

In most situations, when the Deed of Assignment has been exchanged between both parties, it has to be recorded in the land registry to show legal proof that the land has exchanged hands and the public should be aware of the transaction. Such recorded Deed of Assignment come in the form of either a Governor’s consent or registered conveyance. The Deed of Assignment spells out the key issues in the transaction between the Seller and the Buyer so that there won’t be any confusion or assumption after the property has been transferred to the new owner. Such Key issues include:

Signing a Deed of Assignment and having that Deed is your number 1 evidence against another person that is trying to claim ownership of that same land too. If you have a land and no deed yet, i feel sorry for you! Better consult your Lawyer to go draft one for you now to save yourself future problems

1. The Parties’ to the Agreement e.g between Mr A and Mrs K

2. The addresses of both parties and how it is binding on their successors, friends, colleagues and those representing them in any capacity.

3. The history of the land in question how it was first obtained down to the moment its about to be sold including and documents it previously had till this date

4. The agreed cost of the land and the willingness of the Seller to finally accept that price paid for the land

5. The description and size of the land to be transferred.

6. The covenants or promises both parties choose to undertake to perfect the transfer of the document

7. The signature of the parties to the Assignment and Witnesses to the Transaction

8. Finally the section for the Commissioner of Oaths or Governors Consent to sign and validate the agreement.

These are the important features of a Deed of Assignment and must be included in all Documents for it to be valid.

Don’t listen to any Omonile who tells you he doesn’t or the family doesn’t sign a deed of assignment and that it is only a receipt you need. He is only looking for a way to resell your land to another person and to use receipt as a ploy to prevent you from establishing true ownership of your land.

Always consult a property lawyer before you buy a land to help prepare a deed of assignment. It will be your greatest mistake if you don’t have one.

Below is a sample deed of assignment and how it looks so that you don’t fall victim of land swindlers

SAMPLE DEED OF ASSIGNMENT

The Cover of the Deed of Assignment must show the parties to the transaction and the description of the land sold

The first page of the Deed of Assignment must contain the parties to the transaction and the brief history of how the land became the Sellers property

The third page must contain the description of the land to be sold, the surveyor that did it, the cost of the land, the acceptance of the cost of the land and the promises both parties will make to themselves to abide with after the deal has been sealed.

The last page must show the signatures of the parties and the witnesses to that transaction and finally below , the section for the commissioner of oaths to endorse or the Governor to assent his consent to this transaction

Always consult with a lawyer before entering a legal contract.

Borrowed From - Omonile Lawyers

The Importance of Record Copy of a Survey Plan

The Importance of Record Copy of a Survey Plan

A Record Copy (also referred to as Red Copy) is a copy of the original survey carried out by a Registered Surveyor which is lodged in the Cadastral Records department of the Office of the Surveyor General of the State.

The Record Copy is very important because it is required during the processing of any land title. In fact, a survey is not complete until the record copy is lodged.

An evidence of lodgment is usually given to the surveyor after successful lodgment of the record copy.

The time required to lodge a Record Copy depends on the state where the survey was carried out. For a survey carried out by a Registered Surveyor in Lagos state, lodgment of record copy should not take more than 2 months after submission.
It is very important for clients to demand for the evidence from the surveyor so that they don’t have issues during the processing of title because it was not lodged.

HOW To Create Contour Map in Civil 3D

TRAVERSE CALCULATIONS- PROCEDURE

TRAVERSE CALCULATIONS

PROCEDURE FOR TRAVERSE CALCULATIONS

Adjust angles or directions

Determine bearings or azimuths

Calculate and adjust latitudes and departures

Calculate rectangular coordinates

BALANCING ANGLES OF CLOSED TRAVERSES

An example of a calculation involving interior angles is available.

ADJUSTING ANGLES

Adjustments applied to angles are independent of the size of the angle

Methods of adjustment:

Make larger corrections where mistakes were most likely
Apply an average correction to each angle
Or a combination

Never make an adjustment that is smaller than the measured accuracy

DETERMINING BEARINGS OR AZIMUTHS

Requires the direction of at least one line within the traverse to be known or assumed

For many purposes, an assumed direction is sufficient

A magnetic bearing of one of the lines may be measured and used as the reference for determining the other directions

For boundary surveys, true directions are needed

LATITUDES AND DEPARTURES

The latitude of a line is its projection on the north-south meridian and is equal to the length of the line times the cosine of its bearing

The departure of a line is its projection on the east-west meridian and is equal to the length of the line times the sine of its bearing

The latitude is the y component of the line and the departure is the x component of the line

LATITUDES AND DEPARTURES

CLOSURE OF LATITUDES AND DEPARTURES

The algebraic sum of all latitudes must equal zero or the difference in latitude between the initial and final control points

The algebraic sum of all departures must equal zero or the difference in departure between the initial and final control points

CALCULATION OF LATITUDES AND DEPARTURES

Using bearings

Station
Bearing
Length
Latitude
Departure
A
N 26° 10'E
285.10
+255.88
+125.72
B
S 75° 25'E
610.45
-153.70
+590.78
C
S 15° 30'W
720.48
-694.28
-192.54
D
N 1° 42'W
203.00
+202.91
-6.02
E
N 53° 06'W
647.02
+388.48
-517.41
A
MISCLOSURE
-0.71
+0.53

CALCULATION OF LATITUDES AND DEPARTURES

Using azimuths

Station
Azimuth
Length
Latitude
Departure
A
26° 10'
285.10
+255.88
+125.72
B
104° 35'
610.45
-153.70
+590.78
C
195° 30'
720.48
-694.28
-192.54
D
358° 18'
203.00
+202.91
-6.02
E
306° 54'
647.02
+388.48
-517.41
A
MISCLOSURE
-0.71
+0.53

ADJUSTMENT OF LATITUDES AND DEPARTURES

Compass (Bowditch) Rule 

ADJUSTMENT OF LATITUDES AND DEPARTURES

Station
Azimuth
Length
Latitude
Departure
A
+0.08
-0.06
26° 10'
285.10
+255.88
+125.72
B
+0.18
-0.13
104° 35'
610.45
-153.70
+590.78
C
+0.21
-0.15
195° 30'
720.48
-694.28
-192.54
D
+0.06
-0.05
358° 18'
203.00
+202.91
-6.02
E
+0.18
-0.14
306° 54'
647.02
+388.48
-517.41
A
TOTALS
2466.05
-0.71
+0.53

ADJUSTMENT OF LATITUDES AND DEPARTURES

Balanced
Balanced
Station
Latitude
Departure
Latitude
Departure
A
+0.08
-0.06
+255.88
+125.72
+255.96
+125.66
B
+0.18
-0.13
-153.70
+590.78
-153.52
+590.65
C
+0.21
-0.15
-694.28
-192.54
-694.07
-192.69
D
+0.06
-0.05
+202.91
-6.02
+202.97
-6.07
E
+0.18
-0.14
+388.48
-517.41
+388.66
-517.55
A
TOTALS
-0.71
+0.53
0.00
0.00

RECTANGULAR COORDINATES

Rectangular X and Y coordinates of any point give its position with respect to a reference coordinate system

Useful for determining length and direction of lines, calculating areas, and locating points

You need one starting point on a traverse (which may be arbitrarily defined) to calculate the coordinates of all other points

A large initial coordinate is often chosen to avoid negative values, making calculations easier.

CALCULATING X AND Y COORDINATES

Given the X and Y coordinates of any starting point A, the X and Y coordinates of the next point B are determined by:

COORDINATES

Balanced
Balanced
Station
Latitude
Departure
Y-coord
X-coord
A
10000.00
10000.00
+255.96
+125.66
B
10255.96
10125.66
-153.52
+590.65
C
10102.44
10716.31
-694.07
-192.69
D
9408.37
10523.62
+202.97
-6.07
E
9611.34
10517.55
+388.66
-517.55
A
10000.00
10000.00
TOTALS
0.00
0.00

LINEAR MISCLOSURE

The hypotenuse of a right triangle whose sides are the misclosure in latitude and the misclosure in departure.

TRAVERSE PRECISION

The precision of a traverse is expressed as the ratio of linear misclosure divided by the traverse perimeter length.

expressed in reciprocal form

Example

0.89 / 2466.05 = 0.00036090
1 / 0.00036090 = 2770.8

Precision = 1/2771