Starting up; early stages - Introduction to Environmental Impact Assessment - page 112

stored, so that maps of such variables can be displayed, combined and analysed with
speed and ease (Rodriguez-Bachiller 2000). The GIS market is developing rapidly, but
initial setting-up costs are usually expensive, depending on the accessibility of relevant
data. However, Rodriguez-Bacbiller (2000) notes that, in practice:
a…paradox in the use of GIS [is that] their diffusion continues at a fast
pace, while the realisation grows of the relative unsophistication of their
functionality, illustrated in our review by the relatively narrow range of
operations which they are called upon to perform in environmental
matters: map display, map-overlay and intersection, buffering around
given features, multi-factor map algebra, visibility analysis derived from
terrain modelling. It is probably fair to say that, despite the technical
power of GIS as databases, the purely “visual” appeal of their outputs
(maps) has been and still is a major contributor to their success.
The analyst should also be wary of the seductive attraction of quantitative data at the
expense of qualitative data; each type has a valuable role in establishing baseline
conditions. Finally, it should be remembered that all data sources suffer from some
uncertainty, and this needs to be explicitly recognized in the prediction of environmental
effects (see Chapter 5).
4.8 Impact identification
4.8.1 Aims and methods
Impact identification brings together project characteristics and baseline environmental
characteristics with the aim of ensuring that all potentially significant environmental
impacts (adverse or favourable) are identified and taken into account in the EIA process.
When choosing amongst the existing wide range of impact identification methods, the
analyst needs to consider more specific aims, some of which conflict:
• to ensure compliance with regulations;
• to provide a comprehensive coverage of a full range of impacts, including social,
economic and physical;
• to distinguish between positive and negative, large and small, long-term and short-term,
reversible and irreversible impacts;
• to identify secondary, indirect and cumulative impacts as well as direct impacts;
• to distinguish between significant and insignificant impacts;
• to allow a comparison of alternative development proposals;
• to consider impacts within the constraints of an area's carrying capacity;
• to incorporate qualitative as well as quantitative information;
• to be easy and economical to use;
• to be unbiased and to give consistent results;
• to be of use in summarizing and presenting impacts in the EIS.