[R] Dissolve polygon

[Barry Rowlingson]

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

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