Polygon surrounding multiple point selections

Posted by Richard Mort-2 on Sep 17, 2014; 10:02am
URL: http://imagej.273.s1.nabble.com/Background-subtraction-tp5009655p5009661.html

Hello list,

Before I go through the effort of trying to solve this problem I thought
I'd see if somene else has already done the same. I have a spatial
pattern composed of lots of xy positions (see attached plot). I can find
the bounding box for these positions using the code pasted at the end.
How can I find a polygon that joins all the points at the edge of the
pattern?

Best
R

//Find bounding box of multiple xy positions


run("Analyze Particles...", "display");

//some variables
max_x = 0;
max_y = 0;
min_x = 0;
min_y = 0;

//Max value in "XM" column
for (a=0; a<nResults(); a++) {
     if (getResult("XM",a)>max_x)
     {
      max_x = getResult("XM",a);
         }
         else{};
}

//Min value in "XM" column (note: requires max value)
min_x=max_x;
for (b=0; b<nResults(); b++) {
     if (getResult("XM",b)<min_x)
     {
      min_x = getResult("XM",b);
         }
         else{};
}


//Max value in "YM" column
for (c=0; c<nResults(); c++) {
     if (getResult("YM",c)>max_y)
     {
      max_y = getResult("YM",c);
         }
         else{};
}

//Min value in "YM" column (note: requires max value)
min_y=max_y;
for (d=0; d<nResults(); d++) {
     if (getResult("YM",d)<min_y)
     {
      min_y = getResult("YM",d);
         }
         else{};
}

print(min_x);
print(max_x);
print(min_y);
print(max_y);

makeRectangle(min_x, min_y, max_x-min_x, max_y-min_y);

//end

--
Dr Richard Mort
MRC Human Genetics Unit
MRC IGMM
University of Edinburgh
Western General Hospital
Crewe Road
Edinburgh.
EH4 2XU, UK

Tel: [phone]
Fax: [phone]


The University of Edinburgh is a charitable body, registered in
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