Contour.jl: extract the indices of the contour

I am using contour.jl to plot extract contours from interpolated data. Let’s take the sample code from the documentation

for cl in levels(contours(x,y,z))
    lvl = level(cl) # the z-value of this contour level
    for line in lines(cl)
        xs, ys = coordinates(line) # coordinates of this line segment

I need the indices of xs and ys in x and y, a simple world this would be:

ix = indexin(xs, x)
iy = indexin(ys, y)
this_contour = z[ix, iy]

However, xs and ys do not belong exactly to x and y, and I can’t figure out how to extract the indices. Currently indexin returns some ints and some nothings. I haven’t had much luck playing around with round.

The reason I need to do this is that I have an auxiliary array w that has the same shape as z, and I would like to extract the part corresponding to the contours for processing.

Is there some way to do this? I also opened an issue on their GitHub to see if the devs have any thoughts.

X-ref my response on github:

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