[R-sig-Geo] how to show polygons from e00 file ( Grauss-Krüger coordinatensystem) in Google map?

[Torleif Markussen Lunde]

Hi

Like Paul says there are two steps required to accomplish what you want. Below 
you will find two options on how to do this. The import routine is the same 
for both of these, but the first export as png, while the other export 
polygons (better if you are zooming). I recommend you read the documentation 
for all functions, and remember to use citation("package") in your thesis;-)

########################
##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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