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Opportunities for enhancing communication settlement upgrading
with GIT based support tools
images in raster form but they will be predominantly object based, and therefore vector
based.
One concern related to the use of GIT in participatory planning is that the technology itself
has the potential to alienate and exclude non-GIT experts. Although the development and
use of so-called Participatory GIS (PGIS) is an area attracting considerable interest amongst
researchers, the use of such technology carries the risk of undermining participation rather
than promoting it. When used with care and concern for these potential dangers successful
GIS-based joint learning for planning collective action can be realised. Gonzalez (2000) for
example used a PGIS approach in working with local communities in The Philippines,
including data acquisition from aerial photographs and satellite images via a process she
called “participatory image interpretation”.
Planners and engineers are trained to use spatial data that is stored and visualized in
abstract vector formats at various scales. Their basic knowledge in the representation of
reality cartographically, whether in the form of hardcopy maps or in a GIS provides them with
a means to develop, design and communicate ideas for improving a settlement. But training
is required to appreciate and use such abstract representations and many residents of
informal settlements will not have this skill. The use of vector based representations of
settlements therefore cannot be readily used as an instrument for mutual learning between
residents and professionals and may in fact impede, rather than foster, community
participation and knowledge sharing.
Aerial photographs, on the other hand, provide a less abstract image or reality, albeit from an
unusual birds-eye view. Where recent photographs are available they can be used as a
useful source of information in settlement upgrading by both professionals and residents.
Much work at ITC includes the use of both vertical aerial photography and low-cost small
format aerial photography (SFAP) in studies of informal development [some examples of this
are \ (Bruijn 1987; Küpfer, Turkstra et al. 1987; Leelasena, Schaap et al. 1987; Sliuzas 1988)
and the ease with which most residents are able to interpret aerial images of their own area
is well recognised. The ability to create a temporally relevant view of a project area that is
also geometrically compatible with other spatial data sources is an important feature of the
SFAP approach. As such settlements are highly dynamic, SFAP techniques can be used to
provide updated images of the settlement throughout the project cycle. Such a series of
images can be used in a variety of ways beneficial to the upgrading process: to provide a
record of physical development at throughout the project including both improvements and
any additional informal developments; to provide documentary evidence of property
demarcations (Nostrand 1986) and they can be an important instrument in mobilization by
providing residents with an overview of the settlement for identifying problem areas and
exploring possible solutions together with professionals.
The following section discusses informal settlements in Dar es Salaam and how the use of
GIT could contribute to the community based upgrading approaches that are currently being
followed. Two settlements Hanna Nassif and Tabata have been recently upgraded while the
third, Keko Mwanga, is a densely developed but as yet unimproved.
Settlement upgrading, governance and GIT in Dar es Salaam
Changing attitudes to informal housing
Informal settlements have been a feature of Dar es Salaam for many years. Like other
countries in the region, Tanzania inherited an urban planning system that was focussed more
on the needs of the European population (Rakodi 1986; King 1991). In the colonial period the
status of indigenous population was typically seen as only temporarily urban and this view
was reflected in the relative disinterest in their living conditions. However, when the
conditions in so-called African areas were seen to pose a potential threat to public health
generally the colonial authorities may have intervened. Leslie (1963 ) for example reports
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