TRILINEAR PLOT

TRILINEAR PLOT

Graphics Command

Generates a trilinear plot.

The trilinear plot is used for the special case where all rows of 3 variables are positive and sum to 1 (or 100 if percentages are used).

The plot frame is an equilateral triangle. The plot coordinates for point (x1,x2,x3) is determined by drawing a line from each vertex to the opposite side of the triangle such that the line is perpindicular to the opposite side. The intersection of these 3 lines defines the plot point.

In Dataplot,

1. Variable 1 is plotted from the bottom side (= 0) to the center, top vertex (= 1).

2. Variable 2 is plotted from the right side (= 0) to the left, bottom vertex (= 1).

3. Variable 3 is plotted from the left side (= 0) to the right, bottom vertex (= 1).

TRILINEAR PLOT <y1> <y2> <y3>
                        <SUBSET/EXCEPT/FOR qualification>
where <y1> is a variable containing the values for the first component;
            <y2> is a variable containing the values for the second component;
            <y3> is a variable containing the values for the third component;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.

In this syntax, there is a single curve.

TRILINEAR PLOT <y1> <y2> <y3> <groupid>
                        <SUBSET/EXCEPT/FOR qualification>
where <y1> is a variable containing the values for the first component;
            <y2> is a variable containing the values for the second component;
            <y3> is a variable containing the values for the third component;
            <groupid> is a group-id variable;
and where the <SUBSET/EXCEPT/FOR qualification> is optional.

This syntax is used for the case where there are multiple curves on the same plot.

TRILINEAR PLOT Y1 Y2 Y3
TRILINEAR PLOT Y1 X1 Z1
TRILINEAR PLOT Y1 X1 Z1 BATCH

If the TIC MARK LABELS are ON, the 0 and 1 (or 100) label is plotted. No tic marks or intermediate values are plotted. However, if a GRID ON command is entered, grid lines will be drawn.

Axis labels are not generated. You can use the LEGEND command to add labels if desired.

See the Program section below for an example.

As with the PLOT command, the CHARACTER and LINE commands (and the associated attribute setting commands) can be used to control the appearance of the plot.

None

None

PLOT	= Generates a data or function plot.
LINES	= Sets the type for plot lines.
CHARACTER	= Sets the type for plot characters.

Wainer (1997), "Visual Revelations: Graphical Tales of Fate and Deception from Napolean Bonaporte to Ross Perot", Copernicus, pp. 111-118.

Data Analysis

2006/12

 
read y1 y2 y3
0.2 0.5 0.3
0.3 0.6 0.1
0.4 0.1 0.5
0.5 0.2 0.3
0.2 0.2 0.6
0.3 0.4 0.3
0.8 0.1 0.1
end of data
.
let n = size y1
char circ
line blank all
char size 1 all
char fill on all
xlimits 0 1
major x1tic mark number 6
grid on
grid pattern dotted
x1tic marks on
x1tic mark labels on
.
frame corner coordinates 20 18 80 88
.
legend case asis
legend justification center
legend 1 Component A
legend 2 Component B
legend 3 Component C
legend 1 coordinates 50 95
legend 2 coordinates 20 11
legend 3 coordinates 80 11
.
trilinear plot y1 y2 y3