On Mon, Nov 8, 2010 at 11:31 PM, Ab Hu master.rs...@yahoo.com wrote:
Thanks! Works great.
I have more questions on this, so I'll continue here:
Now that I have the weighted mean, is it possible to reduce the size of
mountain based on this weighted mean such the original matrix remains 21x21
On Mon, Nov 8, 2010 at 5:15 PM, Peter Langfelder
peter.langfel...@gmail.com wrote:
If you also need the z coordinate, it simply the mean of the matrix Z.
zCenter = mean(Z)
How can that be right? Suppose your mountain is very flat, so that
your mountain is effectively a cube. The Z values are
On Tue, Nov 9, 2010 at 3:40 PM, Barry Rowlingson
b.rowling...@lancaster.ac.uk wrote:
On Mon, Nov 8, 2010 at 5:15 PM, Peter Langfelder
peter.langfel...@gmail.com wrote:
If you also need the z coordinate, it simply the mean of the matrix Z.
zCenter = mean(Z)
How can that be right? Suppose
-Original Message-
From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-
project.org] On Behalf Of Peter Langfelder
Sent: Tuesday, November 09, 2010 3:49 PM
To: Barry Rowlingson
Cc: r-help@r-project.org; Ab Hu
Subject: Re: [R] Centre of gravity of a mountain
On Tue, Nov 9
zCenter = mean(Z)
How can that be right? Suppose your mountain is very flat, so that
your mountain is effectively a cube. The Z values are all the same,
and so their mean is the same. However the centre of mass is, by
symmetry, clearly at height/2.
Similarly suppose your mountain
Peter Langfelder wrote:
Sorry, I'm not sure what you want to do in points 2-4. Shrink the
mountain vertically or horizontally? You can for example look up image
resizing algorithms if you want to shrink the area under the mountain
but keep the shape of the mountain (approximately) the
Hi all,
I have a matrix of a mountain of form 21x21 and values in them are height
(Z). Using the persp function I can view this mountain in 3D.
Now, I am trying to find a measure to find the centre of gravity (maybe
centroid?) of this mountain. Any idea what would be the best way to go?
--
View
Weighted mean of x and y coordinates (sorry for the pun :)), that is
something like
n = 21
y = matrix( c(1:n), n, n)
x = matrix( c(1:n), n, n, byrow = TRUE)
# These are the Center of mass coordinates:
xCenter = sum(x * Z)/sum(Z);
yCenter = sum(y * Z)/sum(Z);
If you also need the z coordinate,
Thanks! Works great.
I have more questions on this, so I'll continue here:
Now that I have the weighted mean, is it possible to reduce the size of
mountain based on this weighted mean such the original matrix remains 21x21
while the mountain shrinks/converges.
Step for my analysis:
1) Find
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