Creating Historical Digital Census
Boundary Maps for Canada
- a pilot project
Andrey Petrov, Laine Ruus,
Data and GIS Services,
University of Toronto
Presented at CAPDU & IASSIST 2007 (r3)
May 16, 2007
Outline
Background
The project
The result
Background
The basic building block of all larger census
geographic areas in Canada has until
recently (1996) been the enumeration area
(EA)
EAs are defined as the geographic area
canvassed by one census enumerator during
the population census
EAs have not been geostatistically stable
over time.
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EAs are stackable, therefore can cover
>100% of the land area
EAs are the smallest geographic area for
which census statistics have been released
since 1961
The number of EAs changes from census to
census
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EA-level aggregate statistics have been
produced and disseminated by
Statistics Canada since 1961
Availability of census boundary
files & reference maps
Reference maps (raster/print) at the EA-level
are available for the following census:


1971, 1981, 1986, 1991, 1996, 2001, 2006
STC scanned to tiff: 1971-1996 (EAs and urban
CTs)
Boundary files (vector files) at the EA-level
are available for the following census:


1981 (at STC, some lost), 1986, 1991, 1996,
2001, 2006
Canadian Land Inventory EA boundaries from
1971 & 1976
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Demand for historical census data
revitalized with release of each new
census
Academic year
1992-1993
1993-1994
1994-1995
1995-1996
1996-1997
1997-1998
1998-1999
1999-2000
2000-2001
2001-2002
2002-2003
2003-2004
2004-2005
2005-2006
2006-2007
Files
Requests for historic aggregate census data at
UT/DLS, by census year
70
60
50
40
30
20
10
0
1961
1971
1976
1981
1986
1991
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STC has previously done tests of:
Calgary – 1981 census
 Kitchener-Waterloo – 1981 census
 Québec – 1981 census

Our project
Create a historical digital census boundary
files for province of Saskatchewan at EA level
for 1976 & 1981 (projected to NAD83)
Why Saskatchewan?



simple geometry, only 2 CMA/CAs
modest census-to-census boundary changes
no changes to Representation Order (Federal
electoral district boundaries)
Proj contd
Objectives
Test alternative methods of re-creating
historical EA boundary files
 Assess problems and advantages of each
method
 Evaluate feasibility of extending the project
to create a national coverage of historic
census maps

Proj contd
Resources used:






Canadian Land Inventory boundary files for 1976
(rural boundaries only)
STC digital boundary files of Regina & Saskatoon
Geography attribute files 1976 & 1981
EA conversion file 1976-1981
Area master file/road network files
Scanned raster/analog maps of EA boundaries for
Regina, Saskatoon, and rest of Saskatchewan,
1976 & 1981
Proj contd
Design requirements
Use only existing data available for the
entire country
 Develop a repeatable, time & resource
efficient method
 Miminize manual components
 Provide GIS-ready digital output
 Ensure compatibility with other STC
datasets (1996 geographic base)

And the result
Vectorizing from raster maps proved not
feasible
Project successfully produced EA boundary
files for 1976 and 1981 for

Regina and Saskatoon CMAs

Remainder of the province:


58 CSDs missing in 1976
78 CSDs missing in 1981
Inadequate and varying quality of scans
Cluttered with secondary features (lines, labels, grid, etc.)
Dashed lines
All made successful automated vectorization extremely
difficult
Scope of changes: 1976-1981
Extent of changes in Regina and
Saskatoon 1976-1981
Resources required
Hardware: minimum 3.4 GHZ processor,
2GB RAM, 80 GV hard drive, 256 MB multiport video card
Software: ArcGIS 9.x or higher, full package
Wetware: 155 hours, intermediate to
advanced GIS skills
(average 3.0 to 5.0 minutes per EA)
Where does the project go from
here?
Whatever Paula Hurtubise said this
morning………..
Project materials
Report:
http://www.chass.utoronto.ca/~datalib/hurtubise/Report
Statcanr2_060331.doc
Zip file of all project files, including outputs:
http://www.chass.utoronto.ca/~datalib/hurtubise/Saskatc
hewan_EA_projectr.zip