Use of GPS in 2007 Fiji
Census
Why GPS for Census
• GPS Technology next step up after GIS
• Using GPS Technology to address a major development
shortcoming over the years, i.e. pinpointing areas and
households in greatest need for development assistance
• GPS technology enhances the usefulness of census
data as it enables us to relate household records to their
ground location
• Can identify vulnerable households in society ensuring a
targeted response to their needs
• The spatial distribution of each topic raised in the
Census questionnaire can thus be visualized, either as
points or polygons
Why (cont’d)
• Also with this location information, disaster
management strategies can be put in
place to minimize the impact of natural
disasters on the population
• Will overcome the current problems
associated with the use of census data in
defined Police Boundaries and Nursing
Districts.
Funding
UNFPA provided a FJD 200,000 package for
the following
• 200 GPS Units, 20 Laptops
• Wine Langeraar’s consultancy and
associated costs
• Some funding for GPS Operators wages
and travel
UNFPA/FIBoS agreement for use of
equipment in other Pacific Censuses
Personnel
• 10 Officers were trained by the Consultant,
and tasked to carry out validity checks and
download waypoints
• 200 GPS Operators were engaged,
trained over a three day period and each
given a Cheat Sheet
• GPS operators were trained enumerators
who scored lower marks in the selection
test for Enumerators and Supervisors
Personnel
Each Trained GPS Supervisor (FIBoS Staff)
• Provided with a laptop computer
• They operated the basic functions of ArcView
• Transfer waypoints stored in the GPS to his/her
computer
• Display the points recorded by the GPS on top
of the air photo mosaic of his/her District, and
• Could print the result using MS Paint.
Personnel
GPS Operators and Supervisors were provided a
‘Cheat Sheet’: a step-by-step summary of a
particular action compressed onto one page. Six
different Cheat Sheets:
How To:
• Set up the GPS unit
• Record a waypoint
• Download waypoint from a GPS to the computer
• Display the waypoints over the image
• Exporting and Printing JPEG Image Files
Software
• ArcView® GIS version 3.3 with freeware plug-ins obtained from
Minnesota Department of Natural Resources (DNR), USA, and
freeware Enhanced Compression Wavelet plug-ins from
Earth Resource Mapping Pty. Ltd.
• ArcView® Image Analysis, version 1.1
• PC ARC/INFO® version 3.5. ARC/INFO® and ArcView® are
trademarks of Environmental Systems Research Institute, Inc.
(ESRI).
• AutoCAD® version 14 (AutoDesk, Inc.), with Multric® (Mentor
Software, USA) plug-in version 14.1 for ACAD 14.
• Adobe PhotoShop® version 7.0 (Adobe Systems, Inc.).
• Microsoft® Paint
Hardware
• Desktop computer based on the latest
Intel Core 2 Duo chip, 2 Gb RAM, 120 Gb
HD, running on MS Windows XP
professional.
• 21-inch flat screen monitor
• A-3 size laser printer (‘waterproof’ prints)
• A-0 size color ink jet plotter
Field Operation
•
•
•
Started in rural interior and outer islands
during the enumeration period with GPS
operators following the enumerators
Then waypoint gathering continued in
easily accessible areas
Operators were visited regularly for
checks and downloading of waypoints
Three times Waypoint Number
• 1 - The enumerator puts a sticker on the
house where interview takes place and
one on the gate for fenced houses.
Sticker shows a 6-digit unique
identification number: f.i. 123456.
• 2 - A smaller sticker with the same
number (123456) is placed on the
questionnaire form for that household. It
links that questionnaire to that
household.
• 3 - The GPS operator must key in the
same number (123456) as the Waypoint
identification for that location. It links that
GPS location to that household and that
questionnaire. The household location
and the questionnaire could later be
correlated with each other.
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Two Databases Combined
• Upon completion of field work, two databases
are to be created:
– one with as main fields the waypoint number and
latitude and longitude (‘location’ database), and
– another with as main fields the sticker number and
the contents of the questionnaire (‘contents’ or
‘attributes’ database).
• The location and contents databases are
combined using the waypoint number and
sticker number fields as join fields.
• Critical to keep mistakes in waypoint number
and household number at a minimum.
Ways to reduce matching errors
Main causes of matching problems:
– Field: Waypoint number mistakes when input in GPS;
– Office: Punching Errors when household numbers are
entered from questionnaire to database.
• Remedy in the field: Input waypoint numbers into
GPS using barcode reader. There are now GPS
receivers with built-in barcode reader on the
market. Future use?
• Remedy in the office: Questionnaire data input
using intelligent scanning and OCR techniques.
Being implemented in Fiji.
GPS Work in Progress
• Waypoint files at present are being verified
and compiled.
• Some 80,000 household locations have
been verified which is about halfway.
• Most common problem encountered:
Waypoints taken while the GPS unit has
not yet locked on to the satellites.
• Database with household locations ready
by April 2008
Some Problems
Difficulties we encountered included:
• Early stages where operators were taking
waypoints before acceptable precision level
• Loss of stickers as there were two religious
festivals, Diwali and Eid after the Census.
Houses are repainted for the occasion.
• Above meant operators needing to come back to
the office, gather the names, addresses of
residents and the household number before
returning to the field to gather the waypoints.
Photos
Thank You