Presentation on theme: "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."— Presentation transcript:
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
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. Why (cont’d)
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 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. 56
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.