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Transformation of Census Cartography from a conventional
paper map system to an integrated Geographical Information
Technology based system in African Countries – A private
sector perspective with specific reference to Namibia
5. Case study: 2001 Census Cartographic Project in Namibia
5.1 Background
The Republic of Namibia is one of the youngest democracies in the world. After about thirty
years of civil war, the country gained independence from South Africa in 1989. Namibia is
situated in south-western Africa and is bordered by South Africa in the south, Botswana and
Zimbabwe in the east, Zambia and Angola in the north and the Atlantic Ocean in the west.
The country has a population of 1,83 million and a land area of about 1million square
kilometres.
Namibia relies heavily on the economy of South Africa. The biggest industries are diamonds,
fisheries, cattle and tourism. The biggest tourist attractions include the Namib desert and the
Etosha national park where the big five can be seen in a well maintained natural environment.
The far northern part of the country, where more than 50% of the population of the country
resides, provides the tourist with a very interesting view on the traditional way of life in
Namibia.
The first population and housing census after the country came into being, was conducted in
1991. The second census was conducted last year (2001).
During 1999, the Central Bureau of Statistics (CBS) at the National Planning Commission
(NPC) – the government institution ultimately responsible for the census in Namibia – started
with the cartographic work for the 2001 census. It was decided that the 2001 census should be
planned and published with the aid of GIT.
5.2 Project overview
The main aim of the 2001 Census Cartographic Project in Namibia was to systematically sub-divide
the entire country into EAs and to produce a set of maps to be used during the
enumeration phase of the project. The traditional approach for this task was to use a
combination of available hard copy maps and sketch maps. The entire system was, as a result
of this approach, manual. In 1999 the NPC decided to depart from the traditional approach to
census cartographic work and to utilise a GIT-based approach for this important task. Due to
limited in-house capacity, Devinso (one of the companies in the GeoSpace International
group of companies) was awarded a contract to develop a GIT driven census demarcation
methodology and to assist with the implementation and management of the project as a
whole. The initial contract was awarded in November 1999 and project duration was just
under two years.
The project was divided into the following distinct phases or activities:
- Establishment of the GIS infrastructure
- Establishment of a data warehouse
- Evaluation of base map data
- Collection of additional base map data
- EA demarcation and NAMPLAN data collection
- Map production
- Project closure
5.2.1. Establishment of the GIS infrastructure
At the time when the project started (November 1999) no GIS infrastructure existed and very
little GIS capacity was available at the NPC. A study was consequently done to determine the
existence and availability of spatial data for Namibia. Furthermore, a functional specification
based on the unique requirements of the census, was drawn up. Based on the specification, the
system (hardware, software and network) was installed in January 2000.
5.2.2. Establishment of a data warehouse
Once the system was in place, all the relevant data from the official suppliers of spatial data in
Namibia was obtained, converted where required, and incorporated in a spatial data
warehouse.
5.2.3. Evaluation of base map data
A set of criteria was determined for the census maps in each broad settlement type in
Namibia. The data in the system was evaluated against the agreed criteria. The result of this
exercise revealed areas in the country where the available base map data did not meet the
agreed specifications.
5.2.4. Collection of additional base map data
Where the available mapping data did not meet the agreed requirements, additional base map
data was collected, mainly through three methods: a mapping program; digital aerial
photography and enhancement of available maps.
Mapping
Roughly 50% of the total population of Namibia resides in the north of the country in two
predominantly rural areas with a total of 4,5 million hectares, representing only 4,5% of the
total land area of the country. The settlement pattern in those areas is of such a nature that
1:50 000 topographical maps are best suited for census purposes. The available 1:50 000
maps for this part of the country are, however, 30 years and older. This made them virtually
useless given the significant changes in size and distribution of the population over the last 30
years. Due to the fact that up to date small-scale (1:80 000) aerial photography was available,
it was decided to map the most relevant features such as roads, hydrology, homestead
boundaries and housing units. The vector data from the mapping program was superimposed
over the raster image 1:50 000 topographical data to provide what is in essence an updated
1:50 000 map with enough detail for census cartographic purposes.
Digital aerial photography
As a result of the evaluation of existing data, roughly 100 urban areas or larger rural
settlements were identified for the digital aerial survey program. GeoSpace International’s
sophisticated digital aerial photography system was used for this purpose. The photography
mainly covered relatively dense urban or urban type settlements for which no vector data
(town maps) existed. Ortho photomaps at a scale of between 1:10 000 and 1:2 500 –
depending on the requirements – were generated from the images.
Enhancement of available maps
Evaluation of existing base map data furthermore revealed that for some urban areas maps
would exist but, for example, without any street names or suburb boundaries. A dedicated
team of fieldworkers visited these urban areas and either acquired additional data from the
relevant local authority or collected the outstanding data in the field.
5.2.5. EA demarcation and NAMPLAN data collection
After the establishment of a fairly detailed base map for the entire country, the actual sub-dividing
of the country into EAs could begin. This was done through a combination of office-
and fieldwork. The outer boundary of each populated area, referred to as a locality, was
determined and annotated on the GIS generated fieldwork maps. GPS coordinates were taken
to check that the data collected for a given locality was eventually linked to the right polygon
(locality) in the spatial data base. During the fieldwork phase, the position of every institution
in the country was also recorded. This was necessary since institutions require special
enumeration procedures. At the same time a core set of attribute data on the services available
to each locality and institution was also captured. Institutions included were medical,
educational, police, prisons, government buildings, accommodation and community centres.
Data on the following services was captured: water, sanitation, telecommunication, electricity
and accessibility. The data on services available to localities and institutions in Namibia, is
known as the NAMPLAN data base. Localities were then, depending on the settlement type,
grouped together or sub-divided to form Census Enumeration Areas (EAs). In general an EA
consisted of 80-120 households. The data collected during demarcation fieldwork was
captured in the system through a combination of methods. The spatial data was digitised
(heads-up) from the field maps. The attribute data and NAMPLAN data was captured through
manual entry as well as through a process where data from data loggers was downloaded
directly into the data base. All the data recorded with GPS receivers was downloaded directly
into the data base and thereby virtually eliminating data entry errors. Once all the data for a
given region was captured, the data was evaluated and upgraded through an iterative process
by means of the production of series of maps that were scrutinised and corrected (where
necessary) by the census cartographic team. The end product was a detailed data base that
was thoroughly verified and eventually signed off by the cartographic team at the Central
Bureau of Statistics.
5.2.6. Map production
Once the data base was populated and signed off, the base map data together with the census
specific data were used to create a set of about 5 150 unique maps for the enumeration phase
of the census. These maps were generated from the data base using a specially developed map
plotting application. The map creation and the printing of 4 copies of each map were done
over a period of roughly four weeks at the end of the pre-enumeration cartographic project.
The project was a resounding success. It consequently provided what is arguable the most
detailed and accurate mapping data ever available for a population census project in Africa.
The map and map related queries received from the field during the enumeration phase of the
census were negligible compared to what is usually experienced in countries where the
traditional approach to census cartography is followed. Analysis of the Post Enumeration
Survey (PES) conducted shortly after the main census in August last year, revealed an
estimated undercount of 2,2% for the census. This is, as far as could be established, the lowest
undercount rate ever achieved in a census in an African country. Since a census undertaking
consists of many interrelated sub-projects, it can be stated that high quality maps alone cannot
guarantee a successful census. However, a successful census is impossible in the absence of
high quality maps. It can therefore be argued that the superior maps produced for the 2001
census in Namibia by using GIT driven solutions, established the platform for the overall
success of the census as a whole.
5.2.7. Project closure
The entire project was documented and officially handed over to the National Planning
Commission. The final deliverable of the project was the Project Closure Report.
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