Page 187 - Modern Spatiotemporal Geostatistics

168 Modern Spatiotemporal Geostatistics — Chapter 9

Figure 9.1. Daily-averaged ozone exposure maps (ppm) at a region in the
eastern U.S.

the daily-averaged ozone exposure across areas and identify spatiotemporal
exposure patterns of considerable importance in environmental health studies.
Certain differences between spatial and temporal exposure variations may be
due to extra-continua properties of space and time, topographic characteristics
of the region, urban activities, meteorological conditions, etc. The exposure
maps honor the data values at points in which monitoring stations exist.
The support effect

In many geostatistical applications, the support effect (see also Chapter 3,
"The Specificatory Knowledge Base," p. 82) is due to the difference in practice
of the sizes of the samples and the domains (blocks, etc.) to be estimated. It
has been well documented that the support effect can be the cause of incor-
rect mapping estimates (e.g., Rivoirard, 1994). The functional BME analysis
can account for the support effect in a rigorous and systematic manner, as is
illustrated by means of the following simple example.
EXAMPLE 9.2: Consider the case of one hard datum xi at point p : and one soft
(interval) datum X2 at p 2 in the domain of interest. An estimate is sought of
the V-block average Xy(pk) defined by Equation 9.2. The general knowledge
consists of the variograms between all points of the domain, including the two