Message-ID: <CANVKczNTvmwaekTxivzsz7HyqvGJgUMps45ufZQxWvPN2=v-9A@mail.gmail.com>
Date: 2012-07-20T18:11:11Z
From: Barry Rowlingson
Subject: Dissolve polygon
In-Reply-To: <718afeb192e0461280f420320c97c63f@EX-0-HT0.lancs.local>
On Fri, Jul 20, 2012 at 4:51 PM, Celine <bellard.celine at gmail.com> wrote:
> Hi,
>
> I am working with a SpatialPolygonsDataFrame of many islands. There are a
> lot of polygons (islands) composing my SpatialPolygonsDataFrame.
> I want to extract the elevation of each island.
Is each island a row in your SPDF? Or is it just one row, with lots
of island polygons? What does dim(hot) (assuming 'hot' is your SPDF)
say?
> I need to separate the different polygons (like dissolve function in
> arcgis), to have the elevation of each island.
If each island is a row, then its easy, if each island is a separate
loop in a single row, a bit trickier.
How are you going to get the elevation? Do you have a separate data
source, such as a grid of elevations?
Also, try hopping over to the R-sig-geo mailing list. For everything spatial.
Barry
blog: http://geospaced.blogspot.com/
web: http://www.maths.lancs.ac.uk/~rowlings
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