On Mon, 26 Sep 2005, Toni Vi??dez wrote:
> Hi everybody:
> Could anybody help how I solve the next problem?.
> I'm doing interpolation maps of tropospheric ozone of my region, and
after
> create it using IDW, and kriging methods, I want from shapefiles (*.shx,
> *.shp, *.dbf, *.sbx & *.sbn ) create contour over the interpolation
maps.
> Could anybody tell me how do it?.
In replies off-list, I've suggested that using base graphics is simpler
because you can build things up bit by bit with add=TRUE. However, using
the maptools and sp packages, you can look at the example in ?meuse.riv:
spplot(meuse.grid, col.regions=bpy.colors(), main = "meuse.grid",
sp.layout=list(
list("sp.polygons", meuse.sr),
list("sp.points", meuse, pch="+",
col="black")
)
)
which plots a grid of data (your interpolations would need to be converted
to this format) over polygons but under points, where "meuse.sr" is a
SpatialPolygons object. You would then do:
my_polys <- readShapePoly("my_polys.shp")
spplot(meuse.grid, sp.layout=list("sp.polygons", my_polys))
to get something similar. Note that the polygons seem to be plotted under
the image in the example.
> Thanks in advance.
>
> ######################################
> Antonio Viudez Mora
> Departamento de Din??mica
> de Contaminantes
> Fundaci??n CEAM
> Paterna (Valencia)
> tel: 961318190. ext: 216
> e-mail:toni at ceam.es
> ######################################
>
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--
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.Bivand at nhh.no