Bert (in his separate email) is right about learning the basics, and using
R-sig-geo. You're kind of jumping right into the deep end! None the less,
here's an example that should help.
For one thing, you're being more complicated than necessary.
SpatialPointsDataFrame objects can, much of the time, be treated just like
regular data frames. You don't need to extract the @data slot and operate on it.
## example with simple fake data
## for the example, I've decided on groups of three columns
## and 5 rows
set.seed(11198905)
## first, the coordinates and the single column that will be included every
time.
sdf <- data.frame(long=runif(5, -121, -120),
lat=runif(5, 33, 34),
nm=letters[1:5])
## construct a set of data with 9 columns (3 sets of 3)
tmp <- matrix( round(runif(45, 10,20)), nrow=5)
colnames(tmp) <- paste0('v',1:9)
sdf <- cbind(sdf, tmp)
## make it into a SpatialPointsDataFrame
library(sp)
coordinates(sdf) <- c('long','lat')
plot(sdf)
## manually:
## split into three separate SpatialPointsDataFrames, each with three data
columns
s1 <- sdf[,c(1,2:4)]
s2 <- sdf[,c(1,5:7)]
s3 <- sdf[,c(1,8:10)]
## to use a loop, have to calculate which columns are needed each time through
the loop
## (showing intermediate steps in more detail than truly necessary)
for (ic in 1:3) {
## calculate the column numbers
col1 <- ic*3-1
coln <- col1+2
cat('iteration',ic,' selecting columns 1 and',col1,'through',coln,'\n')
sic <- sdf[, c(1, col1:coln)]
## calculate the name of the new SpatialPointsDataFrame
nmi <- paste0('sd',ic)
cat(' assigning to ',nmi,'\n')
## write the current columns to .GlobalEnv
assign( nmi, sic)
}
## now compare s1 with sd1, s2 with sd2, etc.
## they should be the same
## using assign() in this way is often recommended against. An alternative,
which might be better depending on what you need to do with them, would be to
save them as elements of a list object.
--
Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
Lab cell 925-724-7509
On 10/5/18, 7:30 AM, "R-help on behalf of Ivy Pieters"
<r-help-boun...@r-project.org on behalf of icwpiet...@gmail.com> wrote:
Hey there,
I am very much a newbie in the R world. I have to work with R for my
internship. I really hope that someone can help me out here, since it costs me
ages to run and adjust the same script over and over again.
I have a SpatialPointsDataFrame table (sent2field2@data) that I would like
to split into different SpatialPointsDataFrame tables. The first table needs to
consist out of [1:13] columns, the second table needs to consist of
[,c(1,14:25)] the third needs to consist of [,c(1,26:37)]. The name of the
tables need to be Sent2Field2_1, Sent2Field2_2, Sent2Field2_3, etc etc… So only
1,2,3,4 etc need to change within the name. This loop needs to go on until
there are no columns left anymore in the dataset. Then the next step needs to
add coordinates to the table (see script below). The name of the tables need to
be Sent2F2_1, Sent2F2_2, Sent2F2_3, etc etc… So only 1,2,3,4 etc need to change
within the name. The last step projects the table with the added coordinates
into a SpatialPointsDataFrame. See the script below: (up to now I am adjusting
the names manually and running it time after time, i am getting crazy, but I
really don’t know how to make a loop) For now the separate steps are working
fine. I really hope someone can help me out. Looking forward to anyones reply.
Thank you already in advance.
#field2
Sent2Field2_1<-Sent2Field2@data[,1:13]
Sent2F2_1<-cbind(CoordsSent2_F2,Sent2Field2_1)
coordinates(Sent2F2_1) <- ~long+lat
Sent2Field2_2<-Sent2Field2@data[,c(1,14:25)]
Sent2F2_2<-cbind(CoordsSent2_F2,Sent2Field2_2)
coordinates(Sent2F2_2) <- ~long+lat
Sent2Field2_3<-Sent2Field2@data[,c(1,26:37)]
Sent2F2_3<-cbind(CoordsSent2_F2,Sent2Field2_3)
coordinates(Sent2F2_3) <- ~long+lat
Sent2Field2_4<-Sent2Field2@data[,c(1,38:49)]
Sent2F2_4<-cbind(CoordsSent2_F2,Sent2Field2_4)
coordinates(Sent2F2_4) <- ~long+lat
Sent2Field2_5<-Sent2Field2@data[,c(1,50:61)]
Sent2F2_5<-cbind(CoordsSent2_F2,Sent2Field2_5)
coordinates(Sent2F2_5) <- ~long+lat
etc
etc
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______________________________________________
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https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
