Error bars
Syntax: |
GRAPH { `legendtext' } x y { ye1 { xe1 { ye2 { xe2 }}}} |
The optional vectors ye1
, xe1
, ye2
, and xe2
are
interpreted as errors for drawing error bars. You can have symmetric or asymmetric error bars.
Symmetric error bars
For symmetric error bars, the error variable should contain one half of the total error. See the table below.
parameters present | result |
ye1 but not ye2 |
symmetric vertical error bars will be drawn, i.e., at the point (x[j],y[j]) , the error bar is drawnfrom y[j]-ye1[j] to y[j]+ye1[j] |
xe1 but not xe2 |
symmetric horizontal error bars will be drawn, i.e., at the point (x[j],y[j]) , the error bar is drawnfrom x[j]-xe1[j] to x[j]+xe1[j] |
Asymmetric error bars
For asymmetric error bars, the first error variable contains the lower error and the second error variable contains the upper error. See the table below.
parameters present | result |
ye1 and ye2 |
asymmetric vertical error bars are drawn, i.e., at the point (x[j],y[j]) , the error bar is drawnfrom y[j]-ye1[j] to y[j]+ye2[j] |
xe1 and xe2 |
asymmetric horizontal error bars are drawn, i.e., at the point (x[j],y[j]) , the error bar is drawnfrom x[j]-xe1[j] to x[j]+xe2[j] |
Error bar shape
The error bars will have "feet", that is, short line segments, one at each
end of the error bar, which are perpendicular to the error bar. The size of
the foot is the same as the size of the plotting symbol, which can be changed
using the %PLOTSYMBOLSIZE
characteristic or by entering a relative size vector with the
PLOTSYMBOL
characteristic. The error bar will be clipped at the boundaries of the
plotting symbol if the symbol is symmetric under 90°
rotations, for example, a box (symbol number 1
).