[igraph] how to plot a very basic MST with igraph

[Steve Boudreault]

Greetings,

I am new to R, and probably this is a very simple problem with very few
things to do. (Sorry if this is the case.)

Here I go ...

I have a list of about 1000 objects in the file "list.csv". It looks like
this :
alpa   delta
0.923   -12.345
0.912   -11.222
0.812   -11.763
0.902   -11.923
0.942   -12.001
...   ...

Alpha is the X axis and delta is the Y axis.

I would like to produce a very simple minimum spanning tree plot, like the
ones I attached with this message.

The informations I got so far using igraph in R implied using an adjacent
matrix (e.g. "G <- graph.adjacency(as.matrix(D), weighted=TRUE)"). Maybe I
miss something important ... but I fail to understand why I should need a
n x n matrix to make an MST for my list of [X,Y] objects.

Can someone tell me how I can produce a simple minimum spanning tree plot?

Thank you very much for your help.

Best regards,

     Steve Boudreault

-- 
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Steve Boudreault, Ph.D.
CNRS UMR 8111 / GÉPI
Bâtiment 11 - Hipparque     Email: address@hidden
Observatoire de Paris       Phone : +33 (0) 145077868
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