On Fri, 7 May 2010, Everton Emanuel wrote:
Dear all,
I have a small problem, and hope to get some help from you guys.
I have a shape file of Brazilian micro regions; in order to estimate spatial
correlation I need to construct a weight scheme of this shape. However, the
shape contains "islands" that unables its construction. I want to know how
is it possible to manipulate the original shape and erase these islands?
I'm not sure what you mean. If you want to subset a
SpatialPolygonsDataFrame, use the "[" method:
sub <- <logical vector of same length as dim(a)[1]>
asub <- a[sub, ]
If you really want to drop the subset in order to generate spatial
weights, you could do it in this way. However, you could use a graph-based
method that would retain off-shore islands if they are substantive
records. I don't think that you are obliged to drop islands in order to
construct weights.
Hope this helps,
Roger
I appreciate any help,
Everton.
--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: roger.biv...@nhh.no
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