1. Cadastral Principles
Grenville Barnes
TCI Workshop
17 October 2007

2. Content Purpose Cadastral vs Geodetic points Cadastral System
Boundary Types
Cadastral Surveying Process
Cadastral Evidence
Heterogeneity Example
Professional Trends

3. PURPOSE OF CADASTRAL SURVEYING
Demarcate and Identify Boundaries
Collect Evidence to Perpetuate Boundary Location to Promote Security of Tenure
Obtain Data to Represent Boundaries in an Abstract Form (graphical and mathematic evidence)

4. Specific Purpose of a Cadastral System
     Where is the parcel?
    What size (area) is the parcel?
     What are the dimensions of the parcel boundaries?
     What constitutes the parcel boundaries?
   What is the unique identifier of the parcel

5. Multipurpose Land Information System Geodetic Infrastructure
Owners/Lessees
Registry
Information
Source of rights
Restrictions
Encumbrances
Information Layers
Parcel
Identifier
natural resources
infrastructure
socio-economic
Cadastral
Database
Survey
Records
Geodetic Infrastructure

6. Geo-reference Framework
Components of a Cadastral System
Spatial
Geo-reference Framework
Cadastral Survey
Cadastre
INFRASTRUCTURE
MEASUREMENT
MANAGEMENT
The spatial geo-reference framework provides a common reference system for the integration of tenure and other land information.

7. Cadastral vs Geodetic Points
Location of geodetic points is a question of mathematics (coords may vary if datum changes or through readjustment)
Location of cadastral points (parcel corners) is defined by law and evidence (location depends on interpretation of cadastral evidence, especially physical evidence
Cadastral surveying is the process of defining and describing boundary evidence

8. Fixed vs General Boundaries
Fixed - corners/bendpoints are beaconed and boundary is the invisible line in between the beacons
General – a physical feature (hedge, wall, fence, etc.) is accepted as the boundary and mapped

9. Point Typology Parcel corner beacons Indicatory beacons
Control stations (e.g. traverse) – connection to geodetic network
Geodetic Control Points

10. Cadastral Surveying Process
Prior to fieldwork acquire cadastral data on previous surveys of the parcel and adjoining parcels (Reg. 10)
Search for original beacons in field
Survey in found monuments and permanently demarcate control stations (link to geodetic control)
Compare found evidence with previous survey evidence (measurements, beacons, etc)
Recompute and Replace missing beacons
Document survey (report, coord list, comps, fieldbook, etc)
How does this change with use of GPS technology??

11. Cadastral Surveying Challenge
Cadastral boundaries are surveyed by different surveyors at different times to different specifications using different equipment…..
As a result they are a heterogeneous
set of points
Can GPS promote homogeneity?

12. Cadastral Data as Evidence
Physical
beacons
witness marks
improvements
fences
area
coordinates
distances
Survey plan
angles
Index map
Mathematical/
Measurement
Graphical
Verbal

13. Hierarchy of Cadastral Evidence
Physical Parcel
beacons
REALITY
Beacon description
Measurements
Field Notes/ Observations
Computations
Increasing weight of evidence
Coordinates
Area Calculation
Survey Plan
INCREASING ABSTRACTION
Index Map

14. ORIGINAL (PARENT) PARCEL
(200) A B 2
(150)
(150) C D
(200)
ORIGINAL (PARENT) PARCEL
(Assume that coordinates are fixed in database)

15. (200’) B A
198’ 26 27
(150’)
(150’)
Rem of 2
147’ 28 D C
(200’)
Owner of 2 requests three 50’x100’ parcels be subdivided out of parent parcel

16. 26 27 28 Rem of 2 (200) A B 99’ 49’ 99’ (150) 49’ (150) 99’ 49’ D C
Surveyor finds A, B and C and several other original beacons and proves that
these are original, undisturbed and consistent
What happens to the ‘fixed’ coordinates in the database???
Measurements are never exact – they contain systematic and random errors

17. FUNDAMENTAL PRINCIPLES
Equipment is calibrated prior to first use and periodically after that (e.g. 6 monthly)
Measurement to property corners are checked with independent measurements
The original survey provides a definitive description of the parcel boundaries
Relocation of parcel boundaries is determined by a consideration of various evidence

18. Cadastral Field Evidence Matrix of Rural Survey Cost Components
Terrain/Access
Open
Thick bush
Good
Low
Least Expensive
Cadastral Field Evidence
Land Value
More expensive
Most Expensive
Poor
High
Good
Cadastral Record Evidence
Poor
Matrix of Rural Survey Cost Components

19. Surveying Professional Trends
Develop ‘thin’ Survey/Mapping Department that deals primarily with Quality Control and Project Management
Contract out surveys to private sector
Government responsible for geodetic infrastructure
Emergence of surveying profession (private and public)

20. Cadastre 2014 – FIG 20 year Vision
Show the complete legal situation of land, including public rights and restrictions.
Separation between ‘maps’ and ‘registers’ will be abolished.
Cadastral mapping will be defunct; it will be replaced by modeling.
“Paper & pencil cadastre” will be replaced by modern technology.
Cadastre will be highly privatized with public and private sector working closely together.
Procedures for definition of private and public land objects will be identical.

21. Reg. 36 (2)(c)
“A surveyor shall not use a loop traverse closing on his starting point if it is practicable to traverse between two previously fixed stations.”