Dear Erin I use this one that I found on raymond florax's website for spatial econometrics. It works great with points as well as with polygons. PS: I will attach the R file if you need I can send you the files he used to you on another email. Hope it helps you Juan Tomás # import your shapefile using readShapePoly shape <- readShapePoly("columbus.shp",IDvar="POLYID")
# read-in the table containing the data the you want to add to your shapefile # make sure that the table contains a column with a unique identifier corresponding to IDvar tab <- read.table("join_example.txt",header=TRUE) # creates a vector of all polygon IDs #note that it is the "character" version of POLYID (in this example) shpID <- sapply(slot(shape,"polygons"),function(x) slot(x,"ID")) # make the ID variable from the data table into class "character" tabID <- as.character(tab$ID) # match the two unique identifiers # match() needs both its arguments to be of the same class. Here: "character" #### if you want to keep all polygons tab <- tab[match(shpID,tabID),] # matches both IDs and replaces nomatch values by NA rownames(tab) <- shpID shape.mod <- spCbind(shape,tab) #### if you want to delete polygons with no matching data in the table #tab <- tab[shpID%in%tabID,] #shape.mod <- shape.mod[shpID%in%tabID,] # matches and removes the non-matching locations from the table and the original shapefile #shape.mod <- spCbind(shape.mod,tab) On Tue, Nov 1, 2011 at 2:33 AM, Hodgess, Erin <hodge...@uhd.edu> wrote: > Dear R Sig Geo People: > > Is there an equivalent of "join" from ArcGIS 10 in R, please? > > I've been experimenting with "match" but the results between the two are > not the same. > > thanks, > Sincerely, > Erin > > > Erin M. Hodgess, PhD > Associate Professor > Department of Computer and Mathematical Sciences > University of Houston - Downtown > mailto: hodge...@uhd.edu > > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > -- Juan Tomás Sayago Gómez Graduate Research Assistant West Virginia University 886 Chestnut Ridge Road, Room 520 P.O. Box 6825 Morgantown, WV 26506-6825
add_data.r
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