Dear All,
Please consider the snippet at the end of the email.
I often download some maps (in the R format) from
http://www.gadm.org/
However, when I run (typically more than once) a variation of the script
below (based on http://bit.ly/1b3W0Aa ),
I often get
Error in load(url(paste("http://gadm.org/data/rda/";, fileName, "_adm", :
cannot open the connection
In addition: Warning message:
In load(url(paste("http://gadm.org/data/rda/";, fileName, "_adm", :
cannot open: HTTP status was '504 Gateway Time-out'
Does anybody know if gadm blocks repeated attempts to retrieve the same
data?
I am not talking about saturated its bandwidth, just retrieving a few tens
of Mb per day at most.
Many thanks
Lorenzo
##############################################à
## you will need the sp-package
library('sp')
## load a file from GADM (you just have to specify the countries "special
part" of the file name, like "ARG" for Argentina. Optionally you can
specify which level you want to have
loadGADM <- function (fileName, level = 0, ...) {
load(url(paste("http://gadm.org/data/rda/";, fileName, "_adm", level,
".RData", sep = "")))
gadm
}
## the maps objects get a prefix (like "ARG_" for Argentina)
changeGADMPrefix <- function (GADM, prefix) {
GADM <- spChFIDs(GADM, paste(prefix, row.names(GADM), sep = "_"))
GADM
}
## load file and change prefix
loadChangePrefix <- function (fileName, level = 0, ...) {
theFile <- loadGADM(fileName, level)
theFile <- changeGADMPrefix(theFile, fileName)
theFile
}
## this function creates a SpatialPolygonsDataFrame that contains all maps
you specify in "fileNames".
## E.g.:
## spdf <- getCountries(c("ARG","BOL","CHL"))
## plot(spdf) # should draw a map with Brasil, Argentina and Chile on it.
getCountries <- function (fileNames, level = 0, ...) {
polygon <- sapply(fileNames, loadChangePrefix, level)
polyMap <- do.call("rbind", polygon)
polyMap
}
################################################################
################################################################
################################################################
################################################################
spdf <- getCountries(c("ITA","FRA", "DEU","BEL", "LUX", "ESP",
"FIN", "SWE","DNK", "POL", "PRT", "CZE",
"SVK", "SVN", "GBR", "IRL", "ROU", "HUN",
"NLD", "AUT", "BGR","GRC",
"EST","LVA", "LTU","CYP","MLT", "HRV", "CHE"
))
save(spdf,file="gadm_data.Rdata")
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