The complexity of the relations between land use patterns and their spatial
determinants causes the scale of analysis to influence the results. Often,
focus is on one aspect of this scale effect, the spatial resolution. This
study emphasises the influence of a varying spatial extent on the analysis
of land use patterns in six countries in Central America. Statistical techn
iques are used to determine the relationship between six land uses and a nu
mber of potential determining factors, varying both resolution and extent.
Results indicate that the effect of spatial resolution, by aggregating a ba
sic grid to larger units, is small in comparison with other similar studies
. The effect of a varying extent, by keeping either national boundaries or
analysing the entire region at once, on the other hand, is substantial. An
unrealistic redistribution of all major land use types, including a large-s
cale reforestation, is predicted using statistical analysis with the entire
region as extent. When expanding the extent to a unit larger than a countr
y, implicit assumptions concerning market mechanisms and national policies
are adopted that do not correspond to the actual situation. Despite the exi
stence of the Central American Common Market, it cannot be assumed that any
agricultural land use will expand to satisfy an increasing demand in anoth
er country. Findings strongly suggest that any modelling effort at regional
or global level should incorporate a thorough analysis of the effects of s
patial scale on land use change predictions. (C) 2001 Elsevier Science B.V.
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