I recently ran contourf on the image below .
The output of this is as follows
Now when I plot the contour matrix for Number 240,I am getting something like this
Any ideas why there is a line in the middle of the contour,I know that the matrix returned from contourf is a 2xn matrix wherein the first column in each set contains the contour level and the number of vertices at that level.So what I did was from the original contour matrix I removed those columns where it mentions the contour level and the number of vertices at that level.
I also read somewhere that the inputs to contourf should be strictly increasing or decreasing,since the input image contains rows and columns not in strict increasing/decreasing order,do you think that could be one reason as to why there is a line in the middle of the 3rd plot.
Any help will be appreciated.