grid {graphics}R Documentation

Add Grid to a Plot

Description

grid adds an nx by ny rectangular grid to an existing plot.

Usage

grid(nx = NULL, ny = nx, col = "lightgray", lty = "dotted", lwd = NULL,
     equilogs = TRUE)

Arguments

nx,ny number of cells of the grid in x and y direction. When NULL, as per default, the grid aligns with the tick marks on the corresponding default axis (i.e., tickmarks as computed by axTicks). When NA, no grid lines are drawn in the corresponding direction.
col character or (integer) numeric; color of the grid lines.
lty character or (integer) numeric; line type of the grid lines.
lwd non-negative numeric giving line width of the grid lines; defaults to par("lwd").
equilogs logical, only used when log coordinates and alignment with the axis tick marks are active. Setting{equilogs = FALSE} in that case gives non equidistant tick aligned grid lines.

Note

If more fine tuning is required, use abline(h = ., v = .) directly.

See Also

plot, abline, lines, points.

Examples

plot(1:3)
grid(NA, 5, lwd = 2) # grid only in y-direction

data(iris)
## maybe change the desired number of tick marks:  par(lab=c(mx,my,7))
op <- par(mfcol = 1:2)
with(iris,
     {
     plot(Sepal.Length, Sepal.Width, col = as.integer(Species),
          xlim = c(4, 8), ylim = c(2, 4.5), panel.first = grid(),
          main = "with(iris,  plot(...., panel.first = grid(), ..) )")
     plot(Sepal.Length, Sepal.Width, col = as.integer(Species),
          panel.first = grid(3, lty=1,lwd=2),
          main = "... panel.first = grid(3, lty=1,lwd=2), ..")
     }
    )
par(op)
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