Date: May 1, 2013 9:39 PM
Author: David Park
Subject: Re: Intersection points of two contour plots

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