How extract boundary of red region in attached figure.

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varunesh
varunesh on 11 Sep 2018
Edited: varunesh on 13 Sep 2018
Hello All,
Actually, I want to make masking file of data above 1000m hight. I have already found a longitude and latitude of above 1000m height and plot that in red color but I want to just the boundary of this whole red plotted region. Please help me. Thank you so much in advance.
I am attaching figure and data. Below is code which I am using for plotting this.
z2 = z./9.8; z2 = z2';
xx = find((z2>1000));[x,y]=meshgrid(lons,lats);
plot(x,y,'*k')
hold on;plot(x(xx),y(xx),'*r');axis tight;

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Answers (1)

Image Analyst
Image Analyst on 11 Sep 2018
Do you have the Image Processing Toolbox? If so, simply use bwboundaries().
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Image Analyst
Image Analyst on 12 Sep 2018
What do you REALLY want to accomplish? If you get this as an image, what would it help you do that you cannot do now?
varunesh
varunesh on 13 Sep 2018
Edited: varunesh on 13 Sep 2018
I had already said that I want to longitude and latitude of all boundaries. With the help that boundaries I will mask the original data. I have already one example boundary of Tibet(Above to northern India). I am sending you this example boundary and code. You can see that how do I mask data above 1000m height from sea level from the help of this Tibet boundary.
cst = load('tibet_bath1000.txt');
inix = inpolygon(ln,lt,cst(:,1),cst(:,2));
nnum(inix)=[];
ln and lt is original logitude and latitude of data.

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