Re: Extracting points from a contour plot

*To*: mathgroup at smc.vnet.net*Subject*: [mg90409] Re: [mg90391] Extracting points from a contour plot*From*: "W_Craig Carter" <ccarter at mit.edu>*Date*: Tue, 8 Jul 2008 07:48:24 -0400 (EDT)*References*: <200807080626.CAA18073@smc.vnet.net>

Hello AJ, Instead of giving a single command, these steps to extract what you want may be instructive: cp = ContourPlot[Cos[x] + Cos[y] == 1/2, {x, 0, 4 Pi}, {y, 0, 4 Pi}] cp // FullForm p = Position[cp, _Line] lines = Extract[cp, p] verts = lines /. Line[a__] :> a points = Extract[cp, Position[cp, _GraphicsComplex]][[1, 1]] points is a list {{x1,y1},{x2,y2}... and lines is a list of connections between those vertices {{index1,index4,index6..},{...}} (see GraphicsComplex) Good luck, WCC On Tue, Jul 8, 2008 at 2:26 AM, <ajfriend at gmail.com> wrote: > I'm not a Mathematica expert, so hopefully this isn't too stupid of a > question: > > I'm using ContourPlot to plot the curve of zeros of a function of two > variables within a range of vales (0 < x < 1, 0 < y < 1). Now, what I > really want is the list of points that it generates. I've tried > playing with Solve and NSolve, but these are either not working or are > taking too long. What is the easiest way of getting at the list of > points that ContourPlot has generated? Do I have to do something like > InputForm[%] and then cut and paste the list that I want, or is there > some easier way of doing it? > > Or, maybe there is a way of getting the points that I want without > using ContourPlot that I haven't come across yet, or maybe I'm just > not using Solve correctly. > > Any help would be great. > > Thanks, > AJ > > -- W. Craig Carter

**References**:**Extracting points from a contour plot***From:*ajfriend@gmail.com