Centroid of irregular polygons

[jonnylane]

Hi there,

I have a bit of a problem for you. I have recently had to write a program to compute the centroid (centre of area) of a 2d shape. I used a many-point weighted triangle method. The shapes themselves are ROI's of anatomical features on SPECT and MRI scans.

Im writing up my dissertation and I am trying to come up with a scientific definition of a centroid. I've tried "point of rotation at which ACW moment = CW moment = 0,and a few others, but this doesn't sound right in the purely mathematical context.

any ideas?
thanks

 

[dg]

The centroid is simply more known to physicist as "center of mass"...

Anyway this will help: http://mathworld.wolfram.com/GeometricCentroid.html

If not ask again... ;) Dario