Message-ID: <50D3804D.2020203@uni-muenster.de>
Date: 2012-12-20T21:17:01Z
From: Edzer Pebesma
Subject: Convex hull clip on 3D Spatial Objects
In-Reply-To: <006d01cddee5$680382b0$380a8810$@Usherbrooke.ca>
On 12/20/2012 08:08 PM, Nathalie Morin wrote:
> Hello !
>
>
>
> Does sp handle clipping 3D Spatial Objects such as a convex hull envelope
> around SpatialPoints or SpatialGrids ?
more-dimensional grids can be 'clipped' by 2D objects:
library(sp)
# 10 x 20 x 30 grid:
sgdim = c(10,20,30)
SG = SpatialGrid(GridTopology(rep(0,3), rep(10, 3), sgdim))
SGDF = SpatialGridDataFrame(SG, data.frame(val = rnorm(prod(sgdim))))
image(SGDF, axes=TRUE,col = 'grey')
pol = cbind(c(0,50,50,0,0),c(0,0,50,50,0))
lines(pol)
p = Polygon(pol)
sp = SpatialPolygons(list(Polygons(list(p), "p")))
image(SGDF[sp,], axes=TRUE, add=TRUE)
plot(sp, col='#88888888',add=TRUE)
but not by 3D objects. We have no Spatial* classes yet to represent
convex hulls in more than 2D.
>
>
>
> Cheers,
>
>
>
> Nathalie MORIN
>
> Doctorante en t?l?d?tection foresti?re (Ph.D student in remote sensing
> applied to forestry)
>
> Centre d?application et de recherches en t?l?d?tection (CARTEL)
>
> D?partement de G?omatique Appliqu?e
>
> Sherbrooke (QC) CANADA J1K 2R1
>
> T?l. : + 1 (819) 821-8000 #62962
>
> e-mail : <mailto:Nathalie.M.Morin at Usherbrooke.ca>
> Nathalie.M.Morin at Usherbrooke.ca
>
> <http://www.usherbrooke.ca/> Universit? de Sherbrooke
>
>
>
>
>
>
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--
Edzer Pebesma
Institute for Geoinformatics (ifgi), University of M?nster
Weseler Stra?e 253, 48151 M?nster, Germany. Phone: +49 251
8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de
http://www.52north.org/geostatistics e.pebesma at wwu.de