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Geog
4/517 Geographic Data Analysis
Univariate plotsGeog 4/517 Geographic
Data Analysis
Univariate Plots
In describing or characterizing
the observations of an individual variable, there are three basic
properties that are of interest:
-
the location of observations (along the number line in
general (but the geographical analogy is obvious), or how large or small
the values of the individual observations are)
-
the dispersion (sometimes called scale) of the
observations (how spread out they are along the number line, and again the
geographical analogy is obvious)
-
the distribution of the observations (a characterization of the frequency of occurrence of
different values of the variable--do some values occurs more frequently
than other values?)
Univariate plots provide one way to
find out about those properties (and univariate descriptive statistics
provide another).
There are two basic kinds of
univariate, or one-variable-at-a-time plots,
-
Enumerative plots, or plots that show every observation, and
-
Summary plots, that generalize the data into a simplified
representation.
Enumerative
plot examples
Summary
plot examples
Readings:
Owen (The R Guide):
Ch. 4 & 5, section 6.3; Kuhnert & Venebles (An
Introduction...): p. 61-76; Rossiter (Introduction ... ITC):
Ch. 2; sections 3.1-3.6
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