Transcript PPT

GIS BASED CENSUS MAPPING
APPROACHES - AUSTRALIA
EXPERIENCE
Presentation to the UN Experts Group Meeting
UNSD
29 May - 1 June 2007
Alister Nairn
Director - Geography Section
Introduction
• Paper focuses on how GIS
technologies have been utilized for CD
design and map production for the 2006
census in Australia
Census of Population
and Housing
• 5 yearly -2006 Census on 8 August 06
• Census based on delivery and collection of
census forms - 8.5 million forms hand delivered
• 38,704 CDs, 25,000+ field staff to collect, 800+
staff to process
• First results published in June 2007
• Pressure to increase efficiencies
• Mapping is an integral part of the collection
methodology
Collection Districts – Basis for
Enumeration
An Urban CD Map
A Rural CD Map (section)
The Collector Record Book
Spatial Data Requirements –
The Ideal
• An accurate up to date digital map base showing
correct level of detail.
– Roads, water bodies and rivers, transport, parks
– Administrative boundaries – suburbs, LGAs electoral
divisions, state boundaries
– Cadastral property boundaries
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• Location of residential dwellings (addresses)
• Up to date large scale imagery
Data Sources
Without accurate digital base data GIS
efficiencies are not possible –
Sources:
Federal and State mapping agencies
Private sources
ABS strategy was to get the mapping agencies
to cooperate –
A consortium of of Federal and State mapping
agencies – PSMA Australia (Public Sector
Mapping Agencies)
Technology
• GIS system for editing, analysis,
mapping
– Used MapInfo, MapBasic
• Cartographic Enhancement
– Maplex from ESRI
• Database – storage, retrieval of
information
– Oracle
• Conversion / QA software
– SAFE FME
Geography Section - Staffing
• Provides a centralised centre of
expertise for Geography within the ABS
• 25 staff, most with a university degree
and/or GIS experience
– Maintain geographic classification
– Provide GIS services to rest of the
organisation (Census is the largest client)
– Maintain spatial database, evaluate and
implement new spatial technologies.
Census Mapping Project – Process
Design
Phase 1 - CD Alignment
• Red line is the old CD boundary – Black the new
• GIS tools developed to speed up the editing process
for multiple points – work not done by GIS experts
• 10 staff person years of effort in this editing to bring
2001 CDs into alignment with 2006 base mapping.
Phase 2 – CD Design
• Reviewing the 2001 CDs and redesigning in
areas of change (growth or decline in
population)
• Change estimated number of households by
various means
– Address points
– Cadastral parcels
– Information from local government
• Eg GIS SQL query against cadastral parcels
in 2001 versus 2006
SQL query on Spatial Database
Spatial Editing of CDs
Updating CD Attributes
Phase 3 – Map Production
• A large logistical operation
• High quality maps increase efficiency of
the census collection phase
• 69,548 A3 maps
• 7,840 A2 maps
• 5,818 inset maps
• 6,678 Area Supervisor maps
• 102 District Managers maps
Conclusions
• Development of GIS capabilities has
contributed to more efficient Censuses
by:
– Use of GIS to assist in CD design
– Produce excellent maps to aid the
collection process
– Producing quality statistical geography for
analysis and dissemination
Conclusions
BUT
– GIS will only save costs if there is a
reliable source of suitable data and a core
section of people with well developed
technical skills.
– These data resources can require some
institutional development over an extended
period.
THANK YOU