Environmental Engineering Reference
In-Depth Information
of detail depends on the number of input data as well as on their accuracy that
regulates the map resolution and information content.
Data sources can be point information (e.g. different water or soil samples) as
well as spatially continuous data such as remote sensing images, other existing
digital maps (geological maps) or static modelling results (e.g. mean groundwater
levels). In particular, for developing countries such as most of the countries in
Africa, it should be an interesting option to make use of well-developed open
source GIS applications (e.g. GRASSGIS, Quantum GIS, SAGA GIS). However,
since the system is generally static or semi-dynamic through manually switching on
and off different maps/layers/data, process understanding within GIS is limited and
prediction about the future is not possible.
Taking into account the general characteristics and purposes of a GIS map drawn
by O
'
Looney (
2001
), in the context of water services:
Mapping allows data integration from diverse sources (surveys, censuses, space-
borne imagery, etc.) as well as from different disciplines (social, economic,
environmental data). Maps enable systems analysis across borders and across
disciplines: socio-economic boundaries (e.g. state) to ecohydrological bound-
aries (e.g. watershed). Data can be effectively integrated and managed within
GIS.
Maps are powerful visualization tools that, if well prepared (e.g. clear symbols),
are understandable by all stakeholders including parts of the population that
might have no or limited access to education (e.g. analphabetism). Application
of visual tools is particularly important in developing countries.
Visualization of water-poverty relationships and characteristics, such as the
distances between water supply sources as well as the general water supply
infrastructure are easily includable in a GIS system (Toure et al.
2012
).
Land-use conflicts can be mitigated or anticipated through identi
cation of areas
with high conflict potential (e.g. high water resources concurrence), it is espe-
cially advantageous if the groups of interest are included in the land managing
process (Brown and Raymond
2014
).
Since maps highlight where water services are lacking, speci
c resource (e.g.
irrigation water distribution) and support material allocation can be planned and
executed more cost-effectively taking into account local requirements and
conditions (Gerlach and Franceys
2010
; Wellens et al.
2013
), which is advan-
tageous to unspeci
c universal distribution programmes.
Digital (GIS) maps have the advantage that they can be extended or updated
with additional data (e.g. inclusion of new features or improvement of spatial
resolution) as soon as it becomes available. This assures the map signi
cance
over long periods.
GIS maps are printable or distributable in any number and at any scale. How-
ever, the scale depends on the data resolution and quality, thus on map purpose
and related data survey costs. For instance, a coarse map resolution might be
sufficient to locate water supply infrastructure, but might be insufficient to
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