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Vectors

The 2D vectors style draws a vector from (x,y) to (x+xdelta,y+ydelta). The 3D vectors style is similar, but requires six columns of basic data. In both cases, an additional input column (5th in 2D, 7th in 3D) may be used to provide variable (per-datapoint) color information. (see linecolor and rgbcolor variable). A small arrowhead is drawn at the end of each vector.
4 columns:  x  y  xdelta  ydelta
6 columns:  x  y  z  xdelta  ydelta  zdelta

The keywords "with vectors" may be followed by an inline arrow style specifications, a reference to a predefined arrow style, or a request to read the index of the desired arrow style for each vector from a separate column. Note: If you choose "arrowstyle variable" it will fill in all arrow properties at the time the corresponding vector is drawn; you cannot mix this keyword with other line or arrow style qualifiers in the plot command.

plot ... with vectors filled heads
plot ... with vectors arrowstyle 3
plot ... using 1:2:3:4:5 with vectors arrowstyle variable

Example:

plot 'file.dat' using 1:2:3:4 with vectors head filled lt 2
splot 'file.dat' using 1:2:3:(1):(1):(1) with vectors filled head lw 2

splot with vectors is supported only for set mapping cartesian. set clip one and set clip two affect vectors drawn in 2D. See set clip and arrowstyle.

Copyright 1986 - 1993, 1998, 2004 Thomas Williams, Colin Kelley
Distributed under the gnuplot license (rights to distribute modified versions are withheld).