If all of your data frames had enough points then this should work:
myfun1 <- function(le) {
list(one=geosphere::centroid(coordinates(le$one)),
two=geosphere::centroid(coordinates(le$two))
)
}
lapply(ct, myfun1)
To handle the one point case, try the following, which I think works with your
example data, but is untested if there just two points.
It also assumes the data frames are named 'one' and 'two', and will ignore any
others. To handle other names, I think you
could replace $one with [[1]] and $two with [[2]] .
myfun <- function(le) {
list(one=if (length(le$one)>1) geosphere::centroid(coordinates(le$one)) else
coodinates(le$one),
two=if (length(le$two)>1) geosphere::centroid(coordinates(le$two)) else
coordinates(le$two)
)
}
lapply(ct, myfun)
To see a little bit of what's going on, try
myfun(ct[[1]])
myfun1(ct[[1]])
myfun1(ct[[2]])
myfun(ct[[2]])
I would also verify that the length method for objects of class SpatialPoints
does return the number of points, as it appears to:
> class(ct$a$two)
[1] "SpatialPoints"
attr(,"package")
[1] "sp"
> length(ct$a$one)
[1] 3
> length(ct$a$two)
[1] 3
> length(ct$a$two)
[1] 3
> length(ct$b$two)
[1] 1
--
Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
Lab cell 925-724-7509
On 9/10/18, 10:56 AM, "R-sig-Geo on behalf of Ariel Fuentesdi"
<[email protected] on behalf of [email protected]> wrote:
Hi everyone,
I have a list of coordinates called "ct" and I want to extract the
centroids of each sublist, but it only works when it has only 3 or more
points. In ct$b$two only has one point; in that case, I would rescue that
point as If it were a centroid.
This is what I did:
library(dplyr)
library(geosphere)
ct <- list(a = list(one = data.frame(lon = c(-180, -160, -60), lat = c(-20,
5, 0)),
two = data.frame(lon = c(-18, -16, -6), lat = c(-2, 50,
10))),
b = list(one = data.frame(lon = c(-9, -8, -3), lat = c(-1, 25,
5)),
two = data.frame(lon = c(-90), lat = c(-1))))
coordinates(ct$a$one) <- ~lon+lat
coordinates(ct$a$two) <- ~lon+lat
coordinates(ct$b$one) <- ~lon+lat
coordinates(ct$b$two) <- ~lon+lat
s <- 1:length(ct)
ctply <- list()
for (i in s){
for (j in 1:length(ct[[i]])) {
ctply[[i]][j] <- ifelse(test = lengths(ct[[i]][1]) > 2, yes = sapply(X =
ct[[i]][j],
FUN = function(y) geosphere::centroid(slot(y, "coords"))), no =
ct[[i]][j] )
}
}
Thanks in advance
Regards,
Ariel
[[alternative HTML version deleted]]
_______________________________________________
R-sig-Geo mailing list
[email protected]
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
_______________________________________________
R-sig-Geo mailing list
[email protected]
https://stat.ethz.ch/mailman/listinfo/r-sig-geo
