
Re: Intersection points of two contour plots
Posted:
May 1, 2013 9:40 PM


Hi, The given example was just to illustrate. In the original problem, I cannot specify the region function. Also, I have two tables t1 and t2 with a finite number of points, and I use ListContourPlot with the option Contours > {0} to see the contours at z = 0. The solution to my problem occurs when both t1 and t2 intercept at z = 0, as in the example given.
I can reformulate my problem in the following way: Given some contour plot
p0 = ListContourPlot[Table[Sin[3 x*y], {x, 3, 3, .1}, {y, 3, 3, .1}], Contours > {0}, ContourShading > False, DataRange > {{3, 3}, {3, 3}}, ContourStyle > Black];
How to extract the x and y coordinates of the plot p0 in the form of a list of values t0 = {{x1,y2},{x2,y2},....} . ?? I found an old thread (mg98726) involving the same issue, but the answer (mg98760) doesn't help much.
Thanks in advance. Luiz
On Wed, May 1, 2013 at 9:56 AM, djmpark <djmpark@comcast.net> wrote: > Do you want something like this: > > ContourPlot[Sin[3 x y], {x, 3, 3}, {y, 3, 3}, > Contours > {0}, > ContourShading > False, > ContourStyle > Red, > RegionFunction > Function[{x, y}, x y <= 0], > Exclusions > {x == 0, y == 0}] > > > David Park > djmpark@comcast.net > http://home.comcast.net/~djmpark/index.html > > > From: Luiz Melo [mailto:lmelo@ufsj.edu.br] > > > Hi group, > Please consider the example below to illustrate my question (the original > problem is somehow much more complicated): > > t1 = Table[Sin[3 x*y], {x, 3, 3, .1}, {y, 3, 3, .1}]; > > t2 = Table[If[x*y < 0, Sin[3 x*y]], {x, 3, 3, .1}, {y, 3, 3, .1}]; > > p1 = ListContourPlot[t1, Contours > {0}, ContourShading > False, > DataRange > {{3, 3}, {3, 3}}, ContourStyle > Black]; > > p2 = ListContourPlot[t2, Contours > {0}, ContourShading > False, > DataRange > {{3, 3}, {3, 3}}, ContourStyle > {Red, Dashed, Thick}]; > > Show[p1, p2] > > Is there a way to show only the results of the intersection of these two > contour plots? > > Thank you > Luiz >

