image.legend(zmat, x=<<see below>>, y=<<see below>>, size=c(1, 1),
horizontal=T, nint=50)
z.
This should be the matrix that is represented in the image.
Missing values (NA) are allowed.
x and
y
are of length
1, they determine the upper left corner of the legend scale;
if they are vectors of length
2, they specify opposite corners of the
legend scale.
A list containing
x and
y values may be supplied instead (as
x).
If
x is missing, a call to the
locator function is made to determine the
placement (and size, see below).
size and
x are both missing, you are required to enter two points on the
existing plot (with
locator) to specify the opposite corners
of the legend scale.
TRUE, the orientation of the image legend is horizontal.
The size specified includes the image scale and the surrounding box only; the tick marks and axis labels are outside this region.
# put up an image plot, then put up a horizontal legend i <- interp(ozone.xy$x, ozone.xy$y, ozone.median) image(i) image.legend(i) # add a vertical legend with a specific location rx <- range(ozone.xy$x) ry <- range(ozone.xy$y) image(i) # draw boundaries in the background color usa(xlim=rx, ylim=ry, add=T, col=0) # draw dashed lines to ensure the lines are visible everywhere usa(xlim=rx, ylim=ry, add=T, lty=2) image.legend(i$z, x=-74.7, y=43.3, size=c(.5, 1.5), hor=F) title(main="Median Ozone Concentrations in the North East")