[R-sig-Geo] Eliminate duplicate vertices in a SpatialPolygonsDataFrame object
macq at llnl.gov
Sat Jun 16 02:51:57 CEST 2007
I have managed to create several SpatialPoygonsDataFrame objects in
which the polygons have duplicate vertices. That is, there are
duplicate rows in the matrix in "coords" slot of the object.
In most cases, the object has just one polygon, but in at least one
case it has an outer polygon and a hole.
I would really appreciate some suggestions about an efficient way to
remove duplicate rows from the matrix containing the polygon vertices.
I have a solution using an application called Quantum GIS (the same
app I used to create the duplicate rows without realizing it!), but
it's rather awkward and tedious. Surely I can do better in R, but I
haven't managed to learn yet how to extract, edit, update the
contents of the coords slots (especially if there's more than one, as
in a hole).
Any ideas would be very welcome.
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA
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