Information Technology Reference
In-Depth Information
15.0 4.2
16.0 4.9
17.0 6.3
18.0 8.1
Command file:
set term pbm small
set output 'plot.pbm'
set xlabel 'Distance'
set ylabel 'Size'
plot 'indata'
The resulting plot gets saved to (in this case) a PBM graphics format file
called plot.pbm, which can be viewed with the
ImageMagick display
appli-
cation in Linux, or the
Preview
application on Mac OS X, among others.
Resulting graph:
9
'indata'
8
7
6
5
4
3
10
11
12
13
14
Distance
15
16
17
18
This is the simplest possible example of an x-y chart in
gnuplot
. More compli-
cated charts, such as histograms or surface displays, are also possible with addi-
tional commands; and the size, font and locations of the labels can be controlled.
We started with data in tables of numbers, which can be plotted as x-y plots,
histograms and scatter plots, but not all data come in this form. Other types of
data are maps and graphs of relationships and connections.
Maps
Many types of data have a geographical component and are usefully displayed as
maps. A few examples are: the incidence of cancers by region and their possible
