Use of geographic databases (maps)
and other geospatial tools
during the census
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
Overview
 Introduction:

From EA creation to EA map production for enumeration
 Stages in quality control, EA map production and
Database maintenance




Introduction
Quality control
EA map production
Database maintenance
 Other geospatial tools


GIS for logistics and EA management
PDAs with GPS
 Conclusion
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
Introduction
 Accuracy and completeness of census data depend
substantially on the quality of the cartographic base
maps used by enumerators
 A continuous process of quality control and quality
improvement during data conversion allows review of all
map products before distribution to enumerators.
 This involves verification of the correctness of
administrative boundaries by local administrators
 Remaining problems and inconsistencies must be
resolved before the final products can be generated.
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
Stages in quality assurance, output production
and database maintenance
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
Quality Control (component of quality assurance)

Quality control refers to a final check of the digital map
database before the products are released for the census
operation

Normally consists of software and manual checks- some to be
performed on all products, while more complex and time
consuming checks are done on a subset of products using an
appropriate acceptance sampling strategy

Final quality assurance is best performed using printed
hardcopy maps.
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
Verification
 Match between geographic data and attributes

Correctness of the match between boundary data and
attribute data

There should at least one map feature (a point, line, polygon) for
each record in the geographic attribute table
 Verification of several aspects of database integrity

Verification by census cartography staff will involve the
inspection of the following acceptance criteria:




Legibility
sequence of data layers drawn on a map
Map scale
Source and copyright information
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
Quality Control (cont.)
 Verification by local authorities and final administrative
unit check


These boundaries change often, with new states, provinces,
and districts added on a regular basis irrespective of censustaking efforts
Ideally administrative boundaries are frozen by government
decree several months before the census
 Several options for dealing with this problem closer to
the time of the enumeration include:



continuous tracking
boundary changes are announced in advance
determine a freeze date
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
Quality Control (cont.)

If administrative boundary changes continue to occur, then
continuous tracking before the census is an option. As
changes occur, they are immediately committed to the digital
map database.

In some countries, boundary changes are announced in
advance. The census mapping agency can thus schedule work
on those areas for a later stage in the census mapping
process;

The final option is for the census mapping agency to determine
a freeze date and to revise all boundaries at a later stage,
possibly after the census has been taken.
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
EA map production (including map printing)
 Production of enumerator and supervisory maps

This can be done at the main NSO location or in regional
field offices, depending on the type of NSO organizational
structure
 Develop enumerator/supervisory guidelines and training
materials
 Anyway, they should be simple, but contain enough
information to allow easy orientation
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
EA Maps should contain the following information:

Entire enumeration area defined by a clearly indicated boundary line

Some parts of the neighboring areas and other geographic text and
information to facilitate orientation

Features for EA maps should include:






streets and roads
buildings
landmarks
hydrological features
other notable or relevant features, possibly including topography, water bodies,
etc; and
A consistent map legend or map key, including the exact names and codes
of the administrative and enumeration zones, a north arrow, a scale bar,
and a legend explaining the symbols used for geographic features
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
Components of a Hypothetical urban EA map
Buildings
Street Network
Boundaries
Street
Network
Boundaries
Annotation
and symbols
Buildings
Annota
350
349
349
358
358
362
361
374
374
378
377
Building
numbers
Boundaries
61
27
57
35
22
65
62
40
Neatlines and
Annotation
and legend
symbols
Boundaries
31
32
43
63
28
60
41
42
20
21
42
43
44
41
33
34
57
35
22
65
62
40
350
349
6
61
32
63
42
349
60
41
59
20
21
41
42
43
44
350
33
34
64
58
6
6
4
5
61
7
1
62
31
9
5
66
56
59
10
11
6
4
5
7
1
62
10
63
64
65
3
4
57
31
10
11
12
19
13
18
2
74
73
12
67
75
9
58
68
71
358
18
69
3
17
15
16
21
22
82
81
19
25
45
27
28
29
77
78
28
1
38
88
39
21
7
49
51
50
50
11
23
46
45
1
2
3
43
59
32
34
10
378
33
21
377
Building numbers
61
57
65
40
35
22
62
63
28
42
41
60
59
58
20
21
54
358
46
9
26
25
22
2
3
EA
32
34
9
10
21
33
378
Enumeration Area Map
Province:
District:
Locality:
EA-Code:
Church
Building
number
Building numbers
Approximate scale
43
44
41
42
1
Census
2000
61
27
40
57
65
School
Neatlines and legend
45
National Statistical Office July 1998
35
22
62
19
27
16
4
52
377
EA-Code
8
53
45
Hospital
6
61
60
7
10
Locality
17
33
34
District
64
55
47
11
44
54
50
23
Neatlines and legend
31
32
13
15
52
51
Symbols
14
032
0221
00361
N
19
43
Cartania
Chartes
Maptown
49
51
50
58
1
Enumeration Area Map
Province:
District:
Locality:
EA-Code:
27
48
374
16
4
9
14
84
85
24
27
26
25
22
51
87
86
40
12
42
52
27
2
83
39
41
374
53
58
54
88
10
8
28
1
38
33
30
34
44
47
361
32
31
41
9
54
59
52
77
78
43
42
33
12
24
15
29
37
27
28
29
31
32
13
80
36
26
25
21
20
76
22
29
28
40
24
23
84
85
86
41
34
48
82
79
20
361
2
14
33
30
362
18
70
19
30
32
42
43
21
22
35
83
87
42
41
15
16
27
43
31
32
31
68
71
69
17
44
19
30
72
3
37
29
13
20
23
43
29
22
33
12
67
75
14
38
51
81
23
28
74
73
36
26
79
20
3
4
76
80
35
24
18
358
21
20
19
19
13
2
362
70
44
21
12
42
23
43
45
10
63
64
65
57
37
72
20
51
11
2
8
13
14
38
5
66
56
59
37
42
1
60
55
11
2
8
58
Neatli
31
19
43
28
1
60
55
61
27
64
58
59
Building numbers
Annotation
and symbols
45
19
Cartania
Chartes
Maptown
0
02
003
N
Approximate scale
31
45
41
Complete EA map with all components overlaid on one
map display
350
349
61
27
57
65
40
19
32
43
63
28
42
60
41
64
58
59
20
21
7
11
9
8
58
2
3
17
20
30
361
reet
Bonne St
32
Robinson
Street
32
31
41
33
29
79
47
46
45
2
3
44
86
13
7
12
23
53
Bessel Street
4
52
9
22
377
16
11
10
9
25
378
26
8
27
32
34
10
21
Enumeration Area Map
Cartania
Chartes
Maptown
14
84
85
15
52
51
Province:
District:
Locality:
EA-Code:
2
24
51
54
58
27
83
Grinten Street
49
28
1
88
39
Street
50
48
1
77
78
Miller
eet
Tissot Str
50
76
80
Imh of Drive
43
54
81
21
20
19
82
Mollweide Street
40
34
42
18
Cassini Drive
87
41
30
374
59
68
69
37
42
Goode
33
13
70
38
31
12
362
71
43
27
28
29
29
67
36
22
28
21
22
23
Street
20
23
26
25
75
10
3
4
72
35
24
74
73
Cassini Drive
21
19
15
16
63
11
2
ive
44
45
14
18
Lambert Avenue
enue
tor Av
Merca
43
51
64
6
Gall Street
19
13
t
38
65
5
Dr
358
12
kij Street
Krassows
ree
Snyder St
37
66
57
Tobler Street
42
62
Street
56
59
10
Street
31
1
Ortelius
Ptolemy
6
5
4
61
60
eet
e Str
Clark
Eckert Drive
55
41
42
43
44
33
34
1
Main components are:
Street network,
Buildings
EA boundaries layer
Annotation,
Symbols,
Labels
Building numbers
Neatlines
Legend
45
31
35
22
62
33
Symbols
14
032
0221
00361
District
358
EA-Code
Locality
EA
N
17
Building
number
Hospital
Church
School
Approximate scale
0
50
100
200m
Census 2000
National Statistical Office - July 1998
EA map production (including map printing)
 Other Critical Factors

Barcoding



Black and White


Many barcode readers now come with a USB interface with a
decoder either integrated into the unit or separate
The NSO can use preprinted barcode labels or use software
that creates a barcode for each map produced
Good black and white maps can also be photocopied without
loss of information which allows the local staff to produce
additional copies of EA maps as required.
Design based on users experience, keep backup copies,
automate printing
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
Database maintenance

The census cartographic staff should collect the EA maps after
the census and follow-up on any suggested revisions through
an established procedure of incorporating edits into the master
geographic census database

This may require making the corresponding corrections in the
digital census database, or it may require some additional field
checking, or accessing satellite or aerial photo data to verify
changes.

This can be a very involved process but can ensure that the
NSO holds the most current information on the enumeration
areas, which will reduce the workload for cartographic activities
before future censuses or surveys.

It should not, however, delay the release of census results.
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
Database maintenance:

Census mapping office should implement database
maintenance procedures immediately following a census


continuous updating of boundaries and other features as new
information becomes available
During the intercensal period, a clear system of version control
should be implemented

Changes implemented in the database should be documented and
published. For instance, only one or a small group of staff
members should have the authority for committing changes to the
master database.
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
Database maintenance:
 Staff continuity is critical


The census office needs to identify a core staff that will
maintain the database in the intercensal period, provide
geospatial services for other statistical applications such as
sample surveys, and serve as an institutional memory
This will facilitate a smooth operation of census GIS
applications in the next enumeration
 Think long-term

The benefits of a digital geographic census program will
outweigh the considerable costs, but only if the resulting
census database is used for many applications beyond the
core tasks of a census
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
Use of Geospatial Tools during the census
 Support logistical planning and monitoring of census
progress
 Perform real-time or near real-time quality control of the
census database
 Common Geospatial Tools Used During the Census

GIS for logistics and EA management

PDAs with GPS
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
GIS for logistics and EA management
 GIS packages offer network analysis features that:

Allow for immediate access to digital maps and other
geographic information

Allow the planning staff to determine the distances, costs
of travel, and other features

Allow supervisors to monitor the progress of enumerators
as they move data from local and regional offices

Allow the centralization of information exchange between
different geographies
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
PDAs/Hanheld with GPS
 A wide range of options exist with GUI/OS flexibility
 Allows for the collection of census data and geographic
data simultaneously
 Can provide supervisors locations of enumerators
 Collect and send GPS coordinates to the GIS remotely for
real-time data collection
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round
END
UNSD-CELADE Regional Workshop on Census Cartography for the 2010 Latin America’s census round