SPECIFICATIONS FOR CADASTRAL SURVEY
SPECIFICATIONS FOR CADASTRAL SURVEY
Below are specifications for Cadastral / Property Survey
1.Boundary demarcation and beaconing
The boundary lines which must be identified by the land owner or his representative shall be cut clear of obstacles and beaconed at every change of directions in a way that represents the boundaries as identified by the land owner or his representative. All buried beacons must be intervisible.
(A)The demarcation of the boundaries shall be in accordance with the following conditions:
i. The permissible maximum Beacon interval for layouts survey is 250m and 400m for survey of farm land.
ii. Adjacent Boundary Beacons should be intervisible, but where there is obstruction like wall fence, multiple ray observations from proven station
or pair of stations can be used to fix the position of the affected beacon.
iii. When placing a boundary beacon of a new survey, having a common boundary with a longer and already surveyed boundary line, the new
beacon is to be placed exactly on line and confirmed by angular observation.
IV. Where a property lies on both sides of a road, the survey shall be broken into separate parcels so as to preserve the right of way of the road.
V. Irregular Boundaries: Where part of the boundary of a property is irregular (e.g. a river or stream) the traverse lines at the irregular part shall be pegged closed to the river or stream as much as possible. The edges of the irregular boundary shall be detailed in sections through ray method such that will make for easy application of Simpson or Trapezoidal rule for area calculation of the irregular boundary.
(B) The following types of boundary beacons shall be used for property survey:
i. Concrete Beacons of dimensions 18 x 18cm x 75cm shall be used for private property survey.
ii. Concrete Beacons of dimensions 18 x 18cm x 75cm shall be used for Government property survey. (P.B or PBA)
iii. A cross (X) Marks on boundary walls' with pillar numbers shall be cut and painted on the outside of the wall where it intercepts survey line. Public Survey shall carry double arrows.
(2) METHODS OF SURVEY
The permitted method of survey for cadastral survey is closed traverses which shall be run with Glass Arc Theodolite, Total Station or Electronic Theodolite Equipment and Global Positioning System. The traverse must be
carried out to meet the following technical conditions:
i. Minimum accuracy of 1 / 3,000.
ii. The traverse shall start from institu checked government control or private beacons and run on all the property beacons to close back on the same set of controls or other proven controls.
iii. Multiple ray observations from proven stations to fix obstructed property beacons or boundary beacon that fell on wall fence position.
iv. Chain Survey method is allowed within the traverse only for picking of existing site details.
v. Use of Differential GPS.
vi.The insitu check shall be in both angular and linear checks. The angular checks and linear measurements must be made on sets of three (3) beacons to prove that they are all in position and undisturbed. The allowable angular difference is 20'' while allowable linear difference is
1cm.
vii . Where Government controls or
private beacons are
not available over a long distance of not less than 5km use of differential
viii. GPS or astronomical observation with
convergence correction to
the observed Azimuth shall apply.
The angular observations should be maximum spread of 2 zeros with allowable angular difference of 10 seconds.
Control diagram: A simple sketch shall be prepared in the field book of the control net work, showing the connections between permanent survey control stations and the new survey.
Difference between separate observations should not exceed 1cm.
(3) SURVEY INSTRUMENT
The minimal major instrument permitted to be used for property Survey are:
Total Stations or Electronic Theodolite or Glass Arc Theodolite.
Differential GPS (For control establishment or extension)
Calibrated EDM or Calibrated Steel Tape
Linen tape (for offset measurement only)
Leveling Instrument (For Topographical Survey if required)
4. LINEAR MEASUREMENT
Direct Electronic Measurement
Surface taping on fairly level ground
Catenary taping on rough terrain
(5). CONTROL OF BEARINGS
Bearings shall be controlled through the use of dual frequency GPS which shall be made to control bearing points at every 30 traverse stations or the bearings can be controlled through east and west Stellar Observation. The following observation and accuracy requirements shall be adopted:
By GPS
Minimum of 5 satellites must be tracked before taking of readings.
By Stellar Observations
Minimum Azimuth line length of 200m.
3 separate sets of observations (east / west observations).
Minimum allowable Angular difference between east and west paired observation is 10''.
6 FIELD BOOKS
(6.1) All field observations must be entered in the field book clearly with neat booking.
(6.2) Clear Diagrams: Diagrams of plot surveyed must be unambiguously represented in the field book. Such diagrams will also show permanent features within and along areas adjacent to the plot.
(6.3) Electronics field book or electronic recording of readings is allowed but Surveyor must made sufficient effort to keep job data record that can be easily recalled when the need arises.
(7) COMPUTATION
The computations can be done manually, by computer program or electronic data downloading but in all cases it shall include the following:
I. Reduction of bearings showing angular closures.
II. Distances, measured/corrected.
III. Un adjusted / final coordinates/Linear closures.
IV. Area computations.
V. Azimuth computations where necessary
VI. GPS Process data sheet
The required computational accuracies are as follows:-
Deduced bearing to the nearest 10'
Corrections to measured distance for slope, standardization (where applicable) to the nearest mm.
Coordinates to the nearest mm.
Area to be computed to:
3 places of decimals for 10h and under
2 places of decimals for 10h 100ha
1 place of decimal for 100ha 1000ha
to the nearest ha for over 1000ha.
(8) SIZE OF CERTIFIED PLANS
Plans should be produced on stable material of size not less than A4 paper size (29.7cm x 21cm), while record copy shall be produced on film or by any means electronic or platform acceptable to the office of the Surveyor General of the state.
9. ALLOWABLE DRAWING SCALES
The following drawing scales shall be used for plotting:-
(i)1:250
(ii)1:500
(iii) 1:1000
(iv)1:2000
(v) 1:2,500
(vi) 1: 5000
(vii)1:10000
(viii) 1:20000
(ix) 1:25,000
In the production of record copy, different scales may be used for the main survey and the connection where the later is long. Any chosen scale should permit the clear representation of all measured details, bearing, distances and area on the plan.
Electronic copy maps must be prepared using base data with relevant location accuracy.
10. PLOTTING OF PLAN
Plans can be plotted manually or electronically to meet the following conditions:
Plotting should be by rectangular coordinates' details and irregular boundaries by offsets or bearings and distances.
Plans shall show clearly defined plot boundaries, details within and along the boundary.
Electronic or computer aided plotting is allowed provided all conditions stated above are considered.
(11) CONVENTIONAL SIGNS FOR CERTIFIED PLANS
Approved conventional signs to be used (see cartographic specifications).
Graticule lines to be shown in blue. Connections, traverses and bearings to existing survey station to be shown in blue.
Boundaries to be shown in red lines except where they run along frontages of buildings when they should be shown by a red verge.
Offsets to be shown by figures in black between arrows.
(12).Content and representation on Cadastral Plan
I. Title of Survey.
II. Locality Street Town, L.G.A. and State.
III. Scale and with its linear representation.
IV. North Arrow, Origin, Area
V. Bearing and distance of each boundary line to the nearest minute and centimeter respectively.
VI. Bearing and distance of connecting line and control traverse line.
VII. Calculated bearings and distances to be distinguished from direct measurement by use of the letters 'Cal;
VIII.Bearings and distances of each line adopted from a previous survey to be shown with the letter 'P.O' added (meaning per original).
IX. Area of each lot in layouts to be shown to the nearest.
3 places of decimals for 10h and under
2 places of decimals for 10h 100ha
1 place of decimal for 100ha 1000ha
to the nearest ha for over 1000ha.
Area of plots less than 1ha to be given in square meters to 3 places of decimal.
XI. Any measurements to permanent features that will assist the location of boundary beacons.
XII. Topographical features measured by the Surveyor.
XIII.Adjacent lot names or numbers.
XIV. Initial Bearing adopted for the survey to be marked 'I.B.
XV. Number and nature of each survey beacon.
XVI. Place, names street names, etc.
XVII. A certificate by the Surveyor indicating that the plan correctly represents the s u r v e y t h u s : ' C e r t i f i e d t r u e c o p y o f p l a n m a d e b y me.....on..Signature..............
Cadastral Survey Deliverables
The following items shall constitute deliverables to cadastral client:
Four (4) paper copies of finished plan
Two (2) cloth copies of finished plan
One copy of Technical report
All packaged and presented in a presentable envelope, jacket or bag.
TOPOGRAPHICAL SURVEY
Methods of leveling
Any of the following methods may be adopted or as the client may specify Grid leveling, Tachometry, leveling, reciprocal leveling, direct spirit leveling between bench marks/stations of known heights.
Ideally, all levels should be referred to mean Sea Level. However, for some areas, a Bench Mark with an assumed height may be used if the client so desires.
Instrumentation
Any of the following instruments may be used- Engineers Level, Dumpy Level, Digital Level, Total Station, etc.
Accuracy
The minimum accuracy of the elevation difference between two Bench Marks 'D' kilometers apart is given as 24mm D.
Below are specifications for Cadastral / Property Survey
1.Boundary demarcation and beaconing
The boundary lines which must be identified by the land owner or his representative shall be cut clear of obstacles and beaconed at every change of directions in a way that represents the boundaries as identified by the land owner or his representative. All buried beacons must be intervisible.
(A)The demarcation of the boundaries shall be in accordance with the following conditions:
i. The permissible maximum Beacon interval for layouts survey is 250m and 400m for survey of farm land.
ii. Adjacent Boundary Beacons should be intervisible, but where there is obstruction like wall fence, multiple ray observations from proven station
or pair of stations can be used to fix the position of the affected beacon.
iii. When placing a boundary beacon of a new survey, having a common boundary with a longer and already surveyed boundary line, the new
beacon is to be placed exactly on line and confirmed by angular observation.
IV. Where a property lies on both sides of a road, the survey shall be broken into separate parcels so as to preserve the right of way of the road.
V. Irregular Boundaries: Where part of the boundary of a property is irregular (e.g. a river or stream) the traverse lines at the irregular part shall be pegged closed to the river or stream as much as possible. The edges of the irregular boundary shall be detailed in sections through ray method such that will make for easy application of Simpson or Trapezoidal rule for area calculation of the irregular boundary.
(B) The following types of boundary beacons shall be used for property survey:
i. Concrete Beacons of dimensions 18 x 18cm x 75cm shall be used for private property survey.
ii. Concrete Beacons of dimensions 18 x 18cm x 75cm shall be used for Government property survey. (P.B or PBA)
iii. A cross (X) Marks on boundary walls' with pillar numbers shall be cut and painted on the outside of the wall where it intercepts survey line. Public Survey shall carry double arrows.
(2) METHODS OF SURVEY
The permitted method of survey for cadastral survey is closed traverses which shall be run with Glass Arc Theodolite, Total Station or Electronic Theodolite Equipment and Global Positioning System. The traverse must be
carried out to meet the following technical conditions:
i. Minimum accuracy of 1 / 3,000.
ii. The traverse shall start from institu checked government control or private beacons and run on all the property beacons to close back on the same set of controls or other proven controls.
iii. Multiple ray observations from proven stations to fix obstructed property beacons or boundary beacon that fell on wall fence position.
iv. Chain Survey method is allowed within the traverse only for picking of existing site details.
v. Use of Differential GPS.
vi.The insitu check shall be in both angular and linear checks. The angular checks and linear measurements must be made on sets of three (3) beacons to prove that they are all in position and undisturbed. The allowable angular difference is 20'' while allowable linear difference is
1cm.
vii . Where Government controls or
private beacons are
not available over a long distance of not less than 5km use of differential
viii. GPS or astronomical observation with
convergence correction to
the observed Azimuth shall apply.
The angular observations should be maximum spread of 2 zeros with allowable angular difference of 10 seconds.
Control diagram: A simple sketch shall be prepared in the field book of the control net work, showing the connections between permanent survey control stations and the new survey.
Difference between separate observations should not exceed 1cm.
(3) SURVEY INSTRUMENT
The minimal major instrument permitted to be used for property Survey are:
Total Stations or Electronic Theodolite or Glass Arc Theodolite.
Differential GPS (For control establishment or extension)
Calibrated EDM or Calibrated Steel Tape
Linen tape (for offset measurement only)
Leveling Instrument (For Topographical Survey if required)
4. LINEAR MEASUREMENT
Direct Electronic Measurement
Surface taping on fairly level ground
Catenary taping on rough terrain
(5). CONTROL OF BEARINGS
Bearings shall be controlled through the use of dual frequency GPS which shall be made to control bearing points at every 30 traverse stations or the bearings can be controlled through east and west Stellar Observation. The following observation and accuracy requirements shall be adopted:
By GPS
Minimum of 5 satellites must be tracked before taking of readings.
By Stellar Observations
Minimum Azimuth line length of 200m.
3 separate sets of observations (east / west observations).
Minimum allowable Angular difference between east and west paired observation is 10''.
6 FIELD BOOKS
(6.1) All field observations must be entered in the field book clearly with neat booking.
(6.2) Clear Diagrams: Diagrams of plot surveyed must be unambiguously represented in the field book. Such diagrams will also show permanent features within and along areas adjacent to the plot.
(6.3) Electronics field book or electronic recording of readings is allowed but Surveyor must made sufficient effort to keep job data record that can be easily recalled when the need arises.
(7) COMPUTATION
The computations can be done manually, by computer program or electronic data downloading but in all cases it shall include the following:
I. Reduction of bearings showing angular closures.
II. Distances, measured/corrected.
III. Un adjusted / final coordinates/Linear closures.
IV. Area computations.
V. Azimuth computations where necessary
VI. GPS Process data sheet
The required computational accuracies are as follows:-
Deduced bearing to the nearest 10'
Corrections to measured distance for slope, standardization (where applicable) to the nearest mm.
Coordinates to the nearest mm.
Area to be computed to:
3 places of decimals for 10h and under
2 places of decimals for 10h 100ha
1 place of decimal for 100ha 1000ha
to the nearest ha for over 1000ha.
(8) SIZE OF CERTIFIED PLANS
Plans should be produced on stable material of size not less than A4 paper size (29.7cm x 21cm), while record copy shall be produced on film or by any means electronic or platform acceptable to the office of the Surveyor General of the state.
9. ALLOWABLE DRAWING SCALES
The following drawing scales shall be used for plotting:-
(i)1:250
(ii)1:500
(iii) 1:1000
(iv)1:2000
(v) 1:2,500
(vi) 1: 5000
(vii)1:10000
(viii) 1:20000
(ix) 1:25,000
In the production of record copy, different scales may be used for the main survey and the connection where the later is long. Any chosen scale should permit the clear representation of all measured details, bearing, distances and area on the plan.
Electronic copy maps must be prepared using base data with relevant location accuracy.
10. PLOTTING OF PLAN
Plans can be plotted manually or electronically to meet the following conditions:
Plotting should be by rectangular coordinates' details and irregular boundaries by offsets or bearings and distances.
Plans shall show clearly defined plot boundaries, details within and along the boundary.
Electronic or computer aided plotting is allowed provided all conditions stated above are considered.
(11) CONVENTIONAL SIGNS FOR CERTIFIED PLANS
Approved conventional signs to be used (see cartographic specifications).
Graticule lines to be shown in blue. Connections, traverses and bearings to existing survey station to be shown in blue.
Boundaries to be shown in red lines except where they run along frontages of buildings when they should be shown by a red verge.
Offsets to be shown by figures in black between arrows.
(12).Content and representation on Cadastral Plan
I. Title of Survey.
II. Locality Street Town, L.G.A. and State.
III. Scale and with its linear representation.
IV. North Arrow, Origin, Area
V. Bearing and distance of each boundary line to the nearest minute and centimeter respectively.
VI. Bearing and distance of connecting line and control traverse line.
VII. Calculated bearings and distances to be distinguished from direct measurement by use of the letters 'Cal;
VIII.Bearings and distances of each line adopted from a previous survey to be shown with the letter 'P.O' added (meaning per original).
IX. Area of each lot in layouts to be shown to the nearest.
3 places of decimals for 10h and under
2 places of decimals for 10h 100ha
1 place of decimal for 100ha 1000ha
to the nearest ha for over 1000ha.
Area of plots less than 1ha to be given in square meters to 3 places of decimal.
XI. Any measurements to permanent features that will assist the location of boundary beacons.
XII. Topographical features measured by the Surveyor.
XIII.Adjacent lot names or numbers.
XIV. Initial Bearing adopted for the survey to be marked 'I.B.
XV. Number and nature of each survey beacon.
XVI. Place, names street names, etc.
XVII. A certificate by the Surveyor indicating that the plan correctly represents the s u r v e y t h u s : ' C e r t i f i e d t r u e c o p y o f p l a n m a d e b y me.....on..Signature..............
Cadastral Survey Deliverables
The following items shall constitute deliverables to cadastral client:
Four (4) paper copies of finished plan
Two (2) cloth copies of finished plan
One copy of Technical report
All packaged and presented in a presentable envelope, jacket or bag.
TOPOGRAPHICAL SURVEY
Methods of leveling
Any of the following methods may be adopted or as the client may specify Grid leveling, Tachometry, leveling, reciprocal leveling, direct spirit leveling between bench marks/stations of known heights.
Ideally, all levels should be referred to mean Sea Level. However, for some areas, a Bench Mark with an assumed height may be used if the client so desires.
Instrumentation
Any of the following instruments may be used- Engineers Level, Dumpy Level, Digital Level, Total Station, etc.
Accuracy
The minimum accuracy of the elevation difference between two Bench Marks 'D' kilometers apart is given as 24mm D.
Comments
Post a Comment