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Title
Special UNISPACE III volume
Author
Marsteller, Deborah

International Archives of Photogrammetry and Remote Sensing. Vol. XXXII Part 7C2. UNISPACE III, Vienna 1999
7
/ I5PR5
UNIS PACE III- ISPRS Workshop on
“Resource Mapping from Space”
9:00 am -12:00 pm, 22 July 1999, VIC Room B
Vienna, Austria
ISPRS
Figure 2 Number of new software packages released onto the market 1970-1996
An important development problem in less developed countries
(LDCs) is to increase agricultural production in order to
generate income and employment, while simultaneously
protecting the environment and nature conservation areas.
LDC’s are characterised by large workforces in the agricultural
sector (for example 63% of the African labour force works in
agriculture, and up to 90% in some countries). A lack of
agricultural production means that there is slow growth of
effective demand, causing consumer buying power to remain
weak, which dampens economic activity. Eliminating
undernutrition is strongly connected to more rapid agricultural
development, because the majority of the poor in less developed
countries still depend on agriculture for food and income.
Raising agricultural production requires the removal of resource
constraints including adequate water supply, identifying land
suitable for different agricultural activities, developing high
yield plant species, or improving agricultural practices
(fertilisation, herbicide, mechanical ground preparation etc), in
order to increase production, and hence raise demand and
overall economic activity. Remote sensing may contribute to
many of these activities by providing data and derived
information at a regional and local scale.
In conclusion, the provision, distribution and use of information
dominates employment and economic activity in the developed
economies. Precision agriculture, where detailed local scale
geographical and remote sensing information is used to more
precisely input fertilizers, herbicides and pesticides, promises to
cut costs and increase production in developed countires. In the
LDCs, remote sensing and spatial information may contribute to
more efficient agricultural production through regional
planning, land rehabilitation, and monitoring of land use
changes such as conversion of forest to agriculture. In the next
section the level of operational remote sensing activities is
explored.
OPERATIONAL REMOTE SENSING APPLICATIONS
Aerial photographs represent an important branch of remote
sensing, in which visible (and near infrared) light is used to
record conventional photographs from an aircraft. Aerial
photographs are a mature and operational technology in fields
as diverse as photogrammetry, forestry, agriculture, soil science,
social sciences and geolgy. The main difference between aerial
photography and digital imagery is that the interpretation is
done by people, who identify objects and decide on their
significance. With digital imagery, the enhancement, and often
interpretation of objects, is undertaken using a computer.
Two main techniques have emerged for mapping land
resources. The land unit method is a holistic approach which
identifies areas on aerial photographs or remotely sensed images
with common properties, and assigns an attribute class to the
area (Zonneveld 1974; Zonneveld 1988). It is a technique
particularly suited to rapid survey in unmapped areas. In
contrast, GIS and digital image processing of remotely sensed
imagery is a reductionist approach, where the landscape is
viewed as a series of separate data layer, which are combined in
the computer to model environmental and agricultural features
(Skidmore, 1989). The GIS approach is suited for incorporating
quantitative models based on existing map layers, plot