Hi Mike, I tried the rgdal:readOGR, but got an error.
> nc.river<-readOGR("~/hydromaj/hydromaj_arc.shp") Error in readOGR("~/hydromaj/hydromaj_arc.shp") : missing layer Sorry, I am not very familiar with the data structure, but i am looking at the spatialreference.org. Lets see what i get. Thanks, Migun Here is the .prj file content for hydromaj_arc.prj PROJCS["NAD_1983_StatePlane_North_Carolina_FIPS_3200",GEOGCS["GCS_North_American_1983",DATUM["D_North_American_1983",SPHEROID["GRS_1980",6378137.0,298.257222101]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["False_Easting",609601.22],PARAMETER["False_Northing",0.0],PARAMETER["Central_Meridian",-79.0],PARAMETER["Standard_Parallel_1",34.33333333333334],PARAMETER["Standard_Parallel_2",36.16666666666666],PARAMETER["Latitude_Of_Origin",33.75],UNIT["Meter",1.0]] On Mon, Feb 25, 2013 at 9:01 PM, Michael Sumner <mdsum...@gmail.com> wrote: > You need an input projection on the data, it doesn't know what you are > transforming FROM. > > Did you read this with maptools::readShapePoly? Try with rgdal:readOGR > so you get the projection automatically with the object. > > I cannot download the data from the link you provide, but if you post > the text of the .prj files here someone will be able to give you R > code to set it without re-reading. (Explore for yourself on > spatialreference.org). > > Also, "lat,lon" requires a datum like any map projection - you'll need > to find out if you should stay with NAD83 or convert to WGS84 as in > Erin's code. > > Cheers, Mike. > > > > On Tue, Feb 26, 2013 at 12:45 PM, Migun Shakya <microbea...@gmail.com> wrote: >> Hi Erin, >> I tried that but ended up getting this error. Does the spTransform >> function requires the data to be as data.frame? >> Here is what i did to read the data >> >> library(maptools) >> library(rgdal) >> nc.river<-readShapeSpatial("~/hydromaj/hydromaj_arc.shp") #reading the >> shape file >> >> nc1.wgs84 <- spTransform(nc.river,CRS("+proj=longlat +datum=WGS84")) >> Error in spTransform(xSP, CRSobj, ...) : >> No transformation possible from NA reference system >> >> >> Thanks again >> Migee >> >> On Mon, Feb 25, 2013 at 5:47 PM, Hodgess, Erin <hodge...@uhd.edu> wrote: >>> Hi! >>> >>> Suppose your data set is called nc1.df. >>> >>> Then you can do: >>> library(rgdal) >>> nc1.wgs84 <- spTransform(nc1.df,CRS("+proj=longlat +datum=WGS84")) >>> >>> >>> ________________________________________ >>> From: r-sig-geo-boun...@r-project.org [r-sig-geo-boun...@r-project.org] on >>> behalf of Migun Shakya [microbea...@gmail.com] >>> Sent: Monday, February 25, 2013 4:21 PM >>> To: r-sig-geo@r-project.org >>> Subject: [R-sig-Geo] converting from NAD83 datum to lat,lon >>> >>> Hi all, >>> >>> Is there a way/package/trick to convert the NAD83 formatted file to >>> lat lon format? >>> >>> I downloaded the "Major Hydrography" dataset from NC,USA to plot >>> rivers into a NC map. However, the dataset is in NAD83 or in state >>> plane projection, but i need it to be in lat/lon. >>> >>> >>> Any help would be great. >>> >>> >>> Thanks >>> Migee >>> >>> >>> dataset can be found in: >>> http://data.nconemap.com/geoportal/catalog/search/resource/details.page?uuid=%7B2515713B-2CA0-476F-863F-61441A9D6F70%7D >>> >>> >>> The downloaded dataset consist of >>> hydromaj_arc.dbf >>> hydromaj_arc.prj >>> hydromaj_arc.shp >>> hydromaj_arc.shx >>> hydromaj_arc.txt >>> hydromaj_poly.dbf >>> hydromaj_poly.prj >>> hydromaj_poly.shp >>> hydromaj_poly.shx >>> >>> _______________________________________________ >>> R-sig-Geo mailing list >>> R-sig-Geo@r-project.org >>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo >> >> _______________________________________________ >> R-sig-Geo mailing list >> R-sig-Geo@r-project.org >> https://stat.ethz.ch/mailman/listinfo/r-sig-geo > > > > -- > Michael Sumner > Hobart, Australia > e-mail: mdsum...@gmail.com _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo