Dear all.

I am using the akima function to produce 3d contour plots using interp based
on irregular data.

using the eg in the akima manual

library("akima")
data(akima)
plot(y ~ x, data = akima, main = "akima example data")
with(akima, text(x, y, formatC(z,dig=2), adj = -0.1))
## linear interpolation
akima.li <- interp(akima$x, akima$y, akima$z)
image (akima.li, add=TRUE)
contour(akima.li, add=TRUE)
points (akima, pch = 3)

so with this in mind is there a way of obtaining the interpolated value at a
particular coordinate eg at (11.25,6.5) I can see that it as an orange and
should I look at the contour lines I can see what value it produces. However
Is there a way of saying function[11.25,6.5] which provides a value for that
coordinate.

Hope someone can help

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