1. 5 Marzo 2007 Census mapping and Gis Part II: dissemination Fabio Crescenzi Istat, Central Directorate on General Censuses UNECE Training Workshop on Census Technology for SPECA Member Countries (Astana, 7-8 June 2007) Training module on

2. Reference training material 2/12 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/STAT/SER.F/79 UNITED NATIONS PUBLICATION SALES No. 00.XVII.12

3. Dissemination of Census Mapping and Gis Outputs 3/12 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.

4. a) Equivalency and comparability files 4/12 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.

5. b) Reference map library 5/12 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.

6. Thematic maps 6/12 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 viewer’s 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.

7. Thematic mapping of census data 7/12 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.

8. GIS and Digital boundary files 8/12 Demand for digital databases that consist of extractions of the census agency’s 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.

9. Digital census atlases 9/12 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.

10. Mapping viewing software 10/12 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.

11. Mapping packages free of charges. 11/12 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.

12. Internet mapping 12/12 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).