[R-sig-Geo] how to show polygons from SHP file in Google map?

[Torleif Markussen Lunde]

Yes

First: type ?readShapePoly
If it does not help, use Google, Bing, RSiteSearch, etc.
Third: ask R-sig-geo

natSHP.sp <- readShapePoly("nro2.shp", proj4string=CRS("+init=epsg:2166"))
spplot(natSHP.sp, "NATURRAUMO")

To understand the error, try:
system.file("package="maptools")
system.file("shapes/sids.shp", package="maptools")
and
system.file("nro2.shp", package="maptools")

Best
Torleif

On Thursday 04 June 2009 03:02:44 pm Jian Li wrote:
> Dear Torleif,
>
> I just tried to produce another SpatialPolygons like nat.sp from SHP file
> like this following: natSHP.sp <- readShapePoly(system.file("nro2.shp",
> package="maptools")[1], proj4string=CRS("+init=epsg:2166"))
>
> in order to approach it in the same way for saving the information in KML
> file
>
> But it doesn't work. Do you know what's going wrong or do you have any
> better idea?
>
> The nro2.shp is under
> http://jaguar.biologie.hu-berlin.de/~jian/phpMysqlGoogle/arcViewNro2/
> available.
>
> greeting,
> Jian
>
> > ########################
> > ##Export e00 to Google Earth (png)##
> > ########################
> >
> > #1: import using RArcInfo
> >
> > #Set the working directory to where you stored your nat.e00 data
> > setwd('~/e00data') #Use your own path
> >
> > #load the RArcInfo library (for functions e00toavc, get.xxx)
> > require(RArcInfo)
> >
> > #Convert the e00 to SpatialPolygons
> > e00toavc('nat.e00', './nat2')
> > nat.arc <- get.arcdata("./", "nat2")
> > nat.pal <- get.paldata("./", "nat2")
> > require(maptools) #Needed for pal2SpatialPolygons
> > nat.sp <- pal2SpatialPolygons(nat.arc,
> > 	      nat.pal,
> > 	      nat.pal[[1]]$PolygonId[-1],
> > 	      dropPoly1=TRUE,
> > 	      proj4string=CRS("+init=epsg:2166"))
> >
> > #Transform to longlat, WGS84
> > require(rgdal)
> > nat2.sp <- spTransform(nat.sp, CRS("+proj=longlat +ellps=WGS84"))
> >
> > #Set up metadata
> > GSG <- GE_SpatialGrid(nat2.sp)
> >
> > #Ask for the tempdir
> > tmp.dir <- tempdir()
> >
> > #To change the resolution (and line width), change res
> > res <- 5
> > #Make png-file
> > png(file=paste(tmp.dir, "/", "nat.png", sep=""), width=GSG$width*res,
> > height=GSG$height*res,
> > bg="transparent")
> >      par(mar=c(0,0,0,0), xaxs="i", yaxs="i")
> >      plot(nat2.sp, xlim=GSG$xlim, ylim=GSG$ylim, lwd = res)
> > dev.off()
> >
> > #And make the Google earth kml-file
> > kmlOverlay(SGqk, paste(tmp.dir, "/",  "nat.kml", sep=""),
> > paste(tmp.dir, "/", "nat.png", sep=""))
> >
> > #Now, see in td, and you have your kml and png.
> >
> >
> > ###########################################
> > ##Export the same data as polygons (still to Google earth)
> > #The second option is to export as polygons
> > #(See ?kmlPolygon in maptools)
> >
> > out <- sapply(slot(nat2.sp, "polygons"), function(x) { kmlPolygon(x,
> >     name=paste(slot(x, "ID")),
> >     col="transparent", lwd=5, border='black',
> >     description=paste(slot(x, "ID"))) })
> >
> > tf <- tempfile()
> >
> > kmlFile <- file(paste(tf, ".kml", sep=""), "w")
> > cat(kmlPolygon(kmlname="MyGPoly",
> > kmldescription="<i>Masterthesis</i>")$header,
> >     file=kmlFile, sep="\n")
> > cat(unlist(out["style",]), file=kmlFile, sep="\n")
> > cat(unlist(out["content",]), file=kmlFile, sep="\n")
> > cat(kmlPolygon()$footer, file=kmlFile, sep="\n")
> > close(kmlFile)
> > #################
> >
> > Best wishes
> > Torleif
> >
> > On Wednesday 03 June 2009 09:45:45 am Paul Hiemstra wrote:
> > > Hi,
> > >
> > > You have to do two things, read your data and export it to a format for
> > > Google Earth.
> > >
> > > The Cran Spatial Taskview suggests the RArcInfo package to read the e00
> > > files into R. I'm not sure into what format they are loaded. Maybe
> > > readOGR from the rgdal package can also read e00 files, depending on
> > > the GDAL/OGR version you have available.
> > >
> > > If you have your vector file in an R session in a SpatialPolygons
> > > object (see the sp-package), the following code shows an example how to
> > > export the data to a format that Google Earth can read:
> > >
> > > library(rgdal)
> > > data(meuse)
> > > coordinates(meuse) = ~x+y
> > > proj4string(meuse) = CRS("+init=epsg:28992")
> > > proj4string(meuse)
> > > meuse.ll = spTransform(meuse, CRS("+proj=longlat"))
> > > writeOGR(meuse.ll, "meuse.kml", "meuse.kml", driver="KML")
> > >
> > > I'm not sure if the RArcInfo reads the e00 file into a SpatialPolygons
> > > object (Virgillio?), or if it is easy to convert the output from
> > > RArcInfo to an sp-class. rgdal always reads data into an sp-class, but
> > > I'm not sure if this supports the e00 format.
> > >
> > > I hope this e-mail provides you with some clues to work with,
> > >
> > > cheers and good luck with your thesis,
> > > Paul
> > >
> > > Jian Li wrote:
> > > > Dear r-sig-geo Members,
> > > >
> > > > recently, I've been trying to display the information from a e00 file
> > > > (Grauss-Krüger coordinatensystem) in Google map but until now no
> > > > success.
> > > >
> > > > I would be very appreciated if anyone can help me to solve the
> > > > problem which directly concerns my master thesis.
> > > >
> > > > e00 file is under
> > > > http://jaguar.biologie.hu-berlin.de/~jian/phpMysqlGoogle/nat.e00
> > > > available
> > > >
> > > > Thank you in Advanced
> > > >
> > > > Best Regards,
> > > > Jian
> > > >
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