Getting a list of accurate coordinates from a ContourPlot

Question

I have a set of functions d=d(b) defined implicitly by the equation

f(b,d)=0.

I have plotted that equation using ContourPlot. The problem is that I need to get the coordinates drawn in the plot (or maybe get the coordinates using only the equation) in an accurate way. I have already seen this question:

Getting a list of accurate coordinates from a plot

but it seems that the solutions only solve the problem when you use the Plot function. Also, I have tried to use drawing tools, but that doesn't seem so accurate and I would like to get the coordinates of all the points in the plot.

Possible duplicate: https://mathematica.stackexchange.com/questions/20281/get-the-coordinates-from-contourplot-and-regionplot — Michael E2, Jul 20 '21 at 00:30

score 2 · Accepted Answer · answered Jul 20 '21 at 00:17

2

You can use the Cases idea that's usually used with Plot (see this post) if you first send the contour plot (read: GraphicsComplex) through a Normal.

Normal@ContourPlot[Norm@{x, y} == 1, {x, -1, 1}, {y, -1, 1}];
Cases[%, Line[data_] :> data, \[Infinity]][[1]]

{{0.0690086,-0.99758},<<261>>,{0.0690086,-<<17>>}}

answered Jul 20 '21 at 00:17

NonDairyNeutrino

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Perhaps a little bit simpler: ContourPlot[Norm@{x, y} == 1, {x, -1, 1}, {y, -1, 1}][[1]][[1, 1]] – Ulrich Neumann Jul 20 '21 at 10:55

Getting a list of accurate coordinates from a ContourPlot

1 Answers1