Key concepts 3 Spatial data analysis - Spatial Data Analysis: An Introduction for GIS Users - page 61

Scale effect

174 162 169 161

630 651

150 144 161 160

131 127 162 163

548 641

142 148 158 158

Zoning effect

965

968

972

526 979

530

Figure 4.11 The scale and zoning effects.

but if there is a housing estate just inside one edge of the zone then clearly generaliza-
tions about the population of the zone may be unsound. Geographical space can be
divided in an ini nite number of ways. In practice, it is ot en the case that data aggre-
gated over only one set of areal units are available. It may be that no set of zones has
intrinsic meaning about the underlying populations and that the units are 'modii able.
h is problem is sometimes termed the 'modii able areal unit problem' (MAUP)
(Openshaw and Taylor, 1979). h e MAUP is composed of two parts:

h e scale ef ect Statistical analyses based on data aggregated over areas of dif erent
sizes will produce dif erent results.

h e zoning ef ect Two sets of zones can have the same or similar areas but very
dif erent forms and analyses based on two such sets of zones may vary.

h e scale ef ect and the zoning ef ect are illustrated in Figure 4.11. In this example, the
values (representing numbers of people in each area) shown in Figure 4.10 have been
aggregated into new larger zones.
Note that dif erent terms are used in the literature to refer to the two component
parts of the MAUP. For example, for what is termed here the 'scale ef ect' the term
'aggregation ef ect' is sometimes used (e.g. Atkinson and Tate, 2001; Waller and
Gotway, 2004). To add to the confusion, the zoning ef ect is sometimes also referred
to as the aggregation ef ect (e.g. Openshaw and Taylor, 1979). Other terms are also
encountered for both components of the MAUP but, irrespective of this, the key dis-
tinction between the two components is that one deals with the size of zones (here
called the scale ef ect) and the other with changes in their shape or position when the
size of zones is the same or similar (here called the zoning ef ect).