Thanks Barry. The problem is i didnot understand the parameters in the
functions correctly. Thanks for your detailed explanation.

2009/12/10 Barry Rowlingson <b.rowlingson@lancaster.ac.uk>

> On Thu, Dec 10, 2009 at 8:17 PM, rusers.sh <rusers.sh@gmail.com> wrote:
> > Hi all,
> >  I try to use the readOGR and writeOGR in rgdal package to do the
> > conversion KML and Shape files, but failed. Following is my codes for a
> > simulated dataset.
> > #library(rgdal);library(maptools);ogrDrivers()
> > #generate a simulated point SHAPE file,its name is "pointexamle0" and
> save
> > in "h:/example".
> > x<-runif(5)*180;y<-runif(5)*90
> > pointsam<-SpatialPoints(data.frame(x,y), proj4string=CRS("+proj=longlat
> > +ellps=WGS84"))
> > write.pointShape(coordinates(pointsam), df=as(pointsam, "data.frame"),
> > file="h:/example/pointexamle0")
> >
> > #1. Conver SHAPE file to KML file
> > importshp <- readOGR(dsn="h:/example",layer="pointexamle0") #correct
> > proj4string(importshp)<-CRS("+proj=longlat +ellps=WGS84")
> > writeOGR(obj=importshp,dsn="h:/example",driver="KML",layer="output")
> >  #????Errors
> > #Error in writeOGR(obj = importshp, dsn = "h:/example", driver = "KML",
>  :
> >          GDAL Error 4: Failed to create KML file h:/example.
> >
>
>  The devil, as we say, is in the details (which for some reason are
> truncated!):
>
> Details:
>
>    Working out which combination of dsn, layer, and driver (and
>    option) values give the desired output takes time and care, and is
>    constrained by the ability of drivers to write output; many ar
>
> The parameters for writeOGR are:
>
> writeOGR(object, fileName, layerName,driver="KML")
>
> Here 'object' is your R Spatial Points/Poly/etc, 'fileName' is the
> path (including filename) for your output KML, and 'layerName' is a
> label that your layer will get in the KML - you'll see this in the
> layer list in Google Earth, for example.
>
>  Example:
>
> writeOGR(myPoints,"/tmp/test.kml","TestLayer",driver="KML")
>
>
> Barry
> --
> blog: http://geospaced.blogspot.com/
> web: http://www.maths.lancs.ac.uk/~rowlings
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>
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>



-- 
-----------------
Jane Chang
Queen's

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