Diapositiva 1

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5 Marzo 2007
UNECE Training Workshop on Census Technology for
SPECA Member Countries (Astana, 7-8 June 2007)
Training module on
Census mapping and Gis Part II dissemination
Fabio Crescenzi Istat, Central Directorate on
General Censuses
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Reference training material

Handbook on geographic information systems and
digital mapping Chapter III UNITED NATIONS
(2000) - Department of Economic and Social
Affairs Statistics Division Studies in Methods
Series F No. 79 ______________________ ST/ESA/ST
AT/SER.F/79 UNITED NATIONS PUBLICATION SALES No.
00.XVII.12
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Dissemination of Census Mapping and Gis Outputs

The availability of a complete digital database
it is a crucial issue to allow a more effective
data dissemination.
We distinguish two kinds of products for
dissemination Required products Equivalency
and comparability files, Reference map library,
etc. Thematic maps or tools to build users
thematic maps.
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a) Equivalency and comparability files

Geographic equivalency files that indicate how
current reporting units relate to those used in
previous censuses, or how one set of reporting
units relates to another set Data users may
require information about which Eas belong to a
given statistical or administrative output region.
Comparability files. These files list for each
tabulation unit the corresponding EAs that are
part of that output unit. Once such lists have
been defined, aggregation can be done using
standard database operations.
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b) Reference map library

The census office should also produce reference
maps of all reporting units. In some countries,
the census mapping office is legally required to
produce such maps for use by government officials
and the general public.
Reference maps can be disseminated in digital
form as simple graphics, postscript or PDF files.
Reference maps need to be accompanied by a
detailed description of the definitions of each
census geographic area. Problem not all users
will be able to use digital files. Complete sets
of hard-copy reference maps should therefore also
be made available on demand.
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Thematic maps

• Maps communicate a concept or an idea.
• Maps are often meant to support textual
  information. Some things are difficult to explain
  in words and a map display can help to explain
  complicated issues.
• Maps appeal to the viewers curiosity. They
  provide eye-catching anchors on the pages of a
  report. These will get the reader's attention and
  encourage reading the accompanying text.
• Maps summarize large amounts of information
  concisely.

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Thematic mapping of census data

• GIS make easy to produce maps and Census office
  will usually want to produce publication-quality
  maps that illustrate census results and accompany
  published census reports. The final product is
  printed in book form, published on a CD-ROM or
  posted on an Internet Web site.
• Problem It is not possible to cover all possible
  maps of interest for users, but only some maps
  chosen by the statistical office.

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GIS and Digital boundary files

• Demand for digital databases that consist of
  extractions of the census agencys digital
  geographic master database will continue to
  increase.
• Users may use a Gis software and produce its own
  maps.
• Problem The problem, of course, is that such
  users may not have a desktop GIS package
  available that can be used to create maps.

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Digital census atlases

A digital census atlas is aimed at the general
public, schools and other non-expert users. Two
approaches for producing a digital census atlas
are possible. A static census atlas consists of
a collection of maps and other materials that
have been prepared by the census office. It is
essentially a presentation in which the user can
change the sequence of viewing the content, but
cannot change the content itself. A dynamic
census atlas, in contrast, combines a digital GIS
database and census data in a simple mapping
package. The user can use the data to produce
custom maps, which can be printed or copied into
other applications packages.
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Mapping viewing software

Some census offices have developed map viewing
software in-house and distribute these with their
census data products. Problem The maintenance
of such programs is expensive, however, and binds
resources that could otherwise be spent on data
development or dissemination.
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Mapping packages free of charges.

As an alternative, there are several mapping
packages available that are free of charge and
can be distributed with a database. One of these
is the PopMap software developed by the Software
Development Project of the United Nations
Statistics Division of the United Nations
Secretariat, with funding from the United Nations
Population Fund.
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Internet mapping

• Many national statistical organizations have
  embraced the World Wide Web as a means to
  disseminate information and data.
• Web pages range from simple lists and tables of
  census results to sophisticated query interfaces,
  in which the user can request special
  cross-tabulations.
• The Internet is also suitable for presenting and
  distributing geographic information. (The
  simplest option is to present static map images
  that were produced by the statistical office. For
  instance, a series of maps showing census
  variables can be produced using a desktop mapping
  package).

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