Effective%20Tools%20for%20Cadastral%20Surveying%20in%20Latin%20America%20and%20the%20Caribbean - PowerPoint PPT Presentation

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Effective%20Tools%20for%20Cadastral%20Surveying%20in%20Latin%20America%20and%20the%20Caribbean

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Fundamental Principles of Cadastral Surveying. Efficient (short occupations) ... draw cadastral plan. submit documents to Cadastre Office. GPS Methodology. Results ... – PowerPoint PPT presentation

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Title: Effective%20Tools%20for%20Cadastral%20Surveying%20in%20Latin%20America%20and%20the%20Caribbean


1
Effective Tools for Cadastral Surveying in Latin
America and the Caribbean
  • DR. GRENVILLE BARNES

2
Outline
  • Scope of Land Administration Activities in LAC
  • Development of a GPS Methodology for Property
    Surveying
  • Challenges and Design Criteria
  • Cadastral Context
  • Equipment Acquisition and Transfer
  • Geodetic Infrastructure
  • Office and Field Procedures
  • Evolution of Methodology
  • Toolbox Approach
  • IGS Stations as control
  • Real-time corrections
  • Maintaining currency of property information
  • Conclusions and Challenges

3
Problem Statement
GOVERNMENT AWARENESS WILLINGNESS
INFORMAL PROPERTY (UNSURVEYED) est. 80 Rural
60 Urban
SURVEY AND MAP 6,200,000 PARCELS 1998-2008
NO SURVEY SOLUTION
FUNDING AVAILABLE
GPS
4
Effective Tools...
  • Over the past 10 years governments in Latin
    America and the Caribbean have embarked on
    numerous land administration projects with an
    estimated total cost of over US1billion
  • This funding has come from the countries
    themselves, the international banking
    organizations (World Bank and IDB) and the
    bi-lateral donors (USAID, MCC, United Kingdom,
    France, Canada, Japan, Holland etc.)

5
Land Administration Projects and Funding Agency
CARIBBEAN Jamaica (IDB) Trinidad Tobago
(IDB) Bahamas (IDB) Dominican Republic
(IDB) Antigua OECS Countries (OAS) Turks and
Caicos (DFID)
MEXICO (WB IDB)
CENTRAL AMERICA Belize (IDB) Guatemala
(WB) Honduras (WB, EU, IDB) El Salvador (USAID,
WB) Nicaragua (WB, MCC) Costa Rica (IDB) Panama
(WB, IDB)
SOUTH AMERICA Guyana (IDB, DFID) Colombia
(IDB) Ecuador (IDB, WB) Peru (IDB, WB,
USAID) Brazil (IDB) Bolivia (WB, USAID, Neth,
Nordic) Paraguay (IDB) Suriname (Neth. IDB)
http//www.property-registration.org/Project-list
.html
6
  • Cadastral Methodology
  • (challenges and design criteria)

7
Major Challenges
  • The cost of conventional property surveying
    approaches exceeds the value of the land
  • The time required to survey large numbers of
    properties far exceeds the typical length of land
    administration projects (4 - 5 years)
  • LAC countries (circa 1994) do not have the
    geodetic infrastructure to support the use of GPS
  • Shortage of modern technology and qualified
    surveyors

8
Fundamental Principles of Cadastral Surveying
  • Performed by Qualified Professionals
    (education/experience)
  • Minimum requirements dictated by law
  • Calibrated Equipment
  • Measurements checked Independently
  • Surveys Georeferenced to national coordinate
    system

9
Design Criteria for GPS Methodology
  • Efficient (short occupations)
  • Long Base Lines (minimize control)
  • Less Costly (than Conventional Methods)
  • Realistic level of accuracy
  • Realistic level of Technology
  • Flexible
  • Incorporate quality control mechanisms

The methodology must be needs driven
10
Realistic Accuracy
  • Accuracy f (land value, land use, parcel size,
    culture,..)
  • Cadastral Function of Coordinates
  • relocation of property corners
  • re-monumentation
  • abstract representation

1 m
In rural areas where property values are
relatively low, sub-meter accuracy is adequate
for fulfilling the three functions
11
  • Cadastral Methodology
  • (equipment acquisition)

12
Classes of GPS Positioning
increasing complexity
(
and Skill
Requirements
)
and cost

100

35
,
000
mapping
navigation
geodetic
/
15
m
recreational
grade
grade
grade
E
T
Y
5
m
A
RELATIVE
/
C
M
A
I
DIFFERENTIAL
R
X
U
O
1
m
C
POSITIONING
(
)
R
POINT
ABSOLUTE
C
P
A
POSITIONING
P
0
.
5
m
A
dm
cm
mm
13
  • Cadastral Methodology
  • (geodetic infrastructure)

14
Motivation for a New Geodetic Infrastructure
  • Inadequacy of Local Datums
  • Incompatible with GPS Methods
  • Peru
  • Large regional distortions (e.g., The Coast vs.
    the Andes Valleys)
  • The Bahamas
  • Different NAD27 Realizations on Most Islands
  • Crumbling Infrastructure
  • Attrition of Physical Marks
  • Loss of Records

15
Motivation for Not Delaying in Adopting ITRF
16
Geodetic Infrastructure
  • Reference points with coordinates referenced to
    WGS84/ITRF
  • In-country base stations
  • Calibration Site (10-20 Points)
  • local reference points
  • transformation parameters to convert local
  • datum to/from WGS84

17
GPS METHODOLOGY (field and office procedures)
18
GPS Methodology
CALIBRATION OF EQUIPMENT
        before first use         changes in
receiver, software, antenna, firmware, data
collector
        create data dictionary        
recharge batteries         verify available
memory         program receiver         
notify base station
OFFICE PREPARATION
        occupy reference points        
reconnaissance of parcels         draw
provisional field sketch         occupy parcel
corners         collect satellite data
        enter attribute data         reoccupy
corners         draw final field sketch        
transfer data to laptop
FIELD WORK
  • transfer data to office computer
  • obtain data from 2 base stations
  • differentially correct GPS observation
  • export coordinates to spreadsheet

POST-PROCESSING
  • compare corrected coordinates
  • - base stations 1 and 2
  • - 1st and 2nd occupations
  • calculate means (if acceptable)
  • export coordinates to mapping software

VERIFICATION
  • draw cadastral plan
  • submit documents to Cadastre Office

DRAW CADASTRAL PLAN
19
Initial Tests (UF Albania)
  • Occupation times ( 0.5 - 5 min.)
  • Variable base lines (2 km - 200 km)
  • Different types of GPS receivers
  • Two base stations

Results
  • Obtained submeter accuracy with
  • Occupations of 1 min.
  • Base lines up to 200 km
  • Using Trimble Pro XL
  • Verified with dual base stations and double
    occupation

20
Field Testing GPS Methodology
NICARAGUA
ALBANIA
BELIZE
21
Field Testing GPS Methodology
TRINIDAD
PERU
ECUADOR
22
Quality Control Issues
  • Blunder Trapping
  • multipathing
  • no of satellites and geometry
  • trailing off point
  • wrong base station coordinates
  • change in receiver configuration (e.g. datum)
  • Accuracy Check
  • Receiver meets sub-meter accuracy
  • occupation times sufficient

23
Quality Control Mechanisms
  • Calibration
  • checks receiver meets sub-meter accuracy
  • checks occupation times sufficient
  • Local Reference Points
  • checks wrong base station coordinates entered
  • checks change in receiver configuration
  • Dual Occupation
  • checks for multipathing
  • checks for trailing
  • Double Base Station
  • checks wrong base station coordinates
  • second BS acts as back-up

24
EVOLUTION OF GPS METHODOLOGY
25
Evolution of the Cadastral Surveying Methodology
dGPS
  • Initial Concept dGPS
  • Field Experience (Belize, Peru, Albania, etc.)
    Reveals Complexity of the Problem
  • The Methodology Evolves to the Toolbox Concept

Addition of Surveying Tools
Real-time dGPS
dGPS
Orthophotography
Laser Rangefinder
Compass
Tape
26
Boundary Types Surveying Methodologies
Type (i) Surveyed directly using GPS - Post,
fence and bushes not visible in aerial
photography.
Type (ii) Surveyed by offsets using GPS, or by
photo-identification, if clearly visible in
photography. Could also serve as supplementary
ground control.
27
Eccentric Observations
28
Boundary Types Surveying Methodologies
Type (iii) Surveyed by GPS and/or by
photo-identification, if clearly visible in
photography. Could also serve as supplementary
ground control if clearly photo-identifiable.
Types (iv and v) Surveyed by GPS if accessible
and/or by photo-identification, if not accessible
and clearly visible in photography.
29
Boundary Types Surveying Methodologies
Type (vi) Delineated theoretically, can be set
out using real-time dGPS.
30
Cadastral Survey Methodology
(2 Central Base Stations)
BS 2
Reference Marks
BS 1
Rover
Rover
31
Cadastral Survey Methodology
(Local Central Base Stations)
Reference Mark
Rover
Rover
BS/IGS
32
Cadastral Survey Methodology
(Real-Time Corrections via Satellite
Geostationary Communication Satellite (e.g.
Omnistar)
Reference Marks
Corrections (Real Time)
BS
Rover
Rover
33
  • Maintenance Issues

34
Process Constraints to Cadastral Data
Maintenance
National Cadastre Agency
CADASTRAL DATABASE
PROPERTY TRANSACTIONS (Parcel Mutations)
UPDATED PROPERTY DATA (Registry, Tax Roll,
Zoning)
Local Government
Private Sector Surveyors
PROCESS
  • Lack of standards
  • Incompatibility
  • Lack of resources
  • Lack of legal responsibilities
  • Lack of technical capacity
  • Competing interests
  • Competing mandates
  • Lack of Inter-agency coordination
  • Lack of legal framework
  • Incompatibility
  • Lack of technical solution
  • Lack of over-sight entity
  • Informal transactions
  • Limited perceived benefits
  • High cost of surveys
  • Cultural of informality
  • Limited access to services
  • Lack of awareness
  • Lack of information

CONTRAINTS
35
Conclusion
  • Sub-meter GPS is now being used widely in several
    land administration projects
  • It offers a more efficient, less costly solution
    in certain circumstances, but not the total
    solution
  • Even though benefits are proven, GPS technology
    transfer is still an obstacle
  • GPS procedures need to be integrated into a
    complete business process (office to field to
    office)
  • Need for technology extension agents (e.g.
    agriculture)
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