Title: Effective%20Tools%20for%20Cadastral%20Surveying%20in%20Latin%20America%20and%20the%20Caribbean
1Effective Tools for Cadastral Surveying in Latin
America and the Caribbean
2Outline
- 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
3Problem 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
4Effective 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.)
5Land 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)
7Major 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
8Fundamental 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
9Design 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
10Realistic 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)
12Classes 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)
14Motivation 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
15Motivation for Not Delaying in Adopting ITRF
16Geodetic 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
17GPS METHODOLOGY (field and office procedures)
18GPS 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
19Initial 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
20Field Testing GPS Methodology
NICARAGUA
ALBANIA
BELIZE
21Field Testing GPS Methodology
TRINIDAD
PERU
ECUADOR
22Quality 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
23Quality 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
24EVOLUTION OF GPS METHODOLOGY
25Evolution 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
26Boundary 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.
27Eccentric Observations
28Boundary 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.
29Boundary Types Surveying Methodologies
Type (vi) Delineated theoretically, can be set
out using real-time dGPS.
30Cadastral Survey Methodology
(2 Central Base Stations)
BS 2
Reference Marks
BS 1
Rover
Rover
31Cadastral Survey Methodology
(Local Central Base Stations)
Reference Mark
Rover
Rover
BS/IGS
32Cadastral Survey Methodology
(Real-Time Corrections via Satellite
Geostationary Communication Satellite (e.g.
Omnistar)
Reference Marks
Corrections (Real Time)
BS
Rover
Rover
33 34Process 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
35Conclusion
- 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)