Contourf is plotting weird lines. How to remove them?
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Hi,
I'm using hist3 to get bin centers and the elements in each bin. After this I use contourf to plot the data. Unfortunatelly the outputed contour figure has small vertical and horizointal black lines that don't seem to make sense. Please see lines inside red circles for examples:
My code is as follows:
edges = {0:0.2:13 0:0.2:13}; % edges for hist3
insetPos = [.52 .53 .35 .35];
[n,c] = hist3(X,'edges',edges);
figure
heatmap(n) % FEX
% contourmap
axes('Position',insetPos)
box on
contourf(c{1},c{2},n)
I belive the black lines are part of the contour lines, yet they appear where there are no boundries. If I remove the contour lines they also go away.
contourf(c{1},c{2},n,'LineColor','none') % no contour lines
Any tip on how I could keep the contour lines without drawing the "intruding" lines?
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채택된 답변
Kelly Kearney
2020년 5월 22일
When you let contour choose contour levels automatically, it doesn't always choose the levels you really want. In this case, it chooses integer values, which may not be the best way to contour all-integer data. You might have better luck getting the look you want if you specify between-integer levels, e.g.
contourf(c{1}, c{2}, n, -0.5:10.5)
추가 답변 (2개)
Walter Roberson
2020년 5월 22일
Look at n(24,9) and see that it is 1 there, corresponding to x=1.7, y=4.7; n(23,9) is also 1. That is an island of two 1's surrounded by 0's. With the contour levels happening to correspond to the integers, there should be an island there.
spy(n) and you will see there are a number of small islands.
댓글 수: 2
Walter Roberson
2020년 5월 23일
if you take
n.*bwareafilt(n>0,[SIZE, inf])
then it would filter out islands smaller than SIZE pixels
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