R help - Feb 2004 - Clustering with 'agnes'

Hello,

I had a question regarding clustering using the agnes() function from the
'cluster' package.

I was wondering if anyone knew how I can identify cluster points after running
the agnes function.

For example, I created a dataset with points randomly scattered around (0,0),
(0,1) and (1,0). After clustering, the dendrogram shows all the clustered points
and I get the ordering and height and the agglomerative coefficient. But nowhere
do I see the three actual points listed. Although agnes clusters until there is
one main cluster, it is clear that at three clusters, each of the clusters
consist of points around the three main points. I was wondering if there was any
way in which I can have R give me the actual cluster points at three (or any
number, for that matter) clusters, ie (0,0), (0,1) and (1,0). A visual display
of the clusters would be even better.

I have tried using idenfity after converting the agnes object to an hclust
object, but that only gives me a listing of the points in each cluster.

I hope this question is clear. I am a little new with both clustering and using
R for clustering, so please ask me to clarify if anything is unclear.

Your help would be most appreciated!

With regards,
Arnav



	[[alternative HTML version deleted]]

Arnav Sheth wrote:
> Hello,
> 
> I had a question regarding clustering using the agnes() function from the
'cluster' package.
> 
> I was wondering if anyone knew how I can identify cluster points after
running the agnes function.
> 
> For example, I created a dataset with points randomly scattered around
(0,0), (0,1) and (1,0). After clustering, the dendrogram shows all the clustered
points and I get the ordering and height and the agglomerative coefficient. But
nowhere do I see the three actual points listed. Although agnes clusters until
there is one main cluster, it is clear that at three clusters, each of the
clusters consist of points around the three main points. I was wondering if
there was any way in which I can have R give me the actual cluster points at
three (or any number, for that matter) clusters, ie (0,0), (0,1) and (1,0). A
visual display of the clusters would be even better.
> 
> I have tried using idenfity after converting the agnes object to an hclust
object, but that only gives me a listing of the points in each cluster.
> 
> I hope this question is clear. I am a little new with both clustering and
using R for clustering, so please ask me to clarify if anything is unclear.
> 
> Your help would be most appreciated!
See the example of ?agnes, where the points are labeled.
Most easily use agnes() on a data.frame with rownames.

Uwe Ligges





> With regards,
> Arnav
> 
> 
> 
> 	[[alternative HTML version deleted]]
> 
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