I am trying to convert a bunch of points to polygons.
I found a nice example of what I'm trying to accomplish here: Convert data frame containing coordinates of polygons to sf
I'd like to try their method, but I don't have the skills to go from:
# how I see the points after read_csv - simply 3 columns lon, lat, id
df<-tibble(
lon = c(-119.036,-119.002,-119.010,-119.044,-119.036,-119.002,-118.968,-118.977,-119.010,-119.002),
lat = c(23.097,23.105,23.136,23.128,23.097,23.105,23.112,23.143,23.136,23.105),
id = c(1,1,1,1,1,2,2,2,2,2)
)
to:
# how i want the info organized to work off of stkoverflow eg linked above
df<-tibble::tribble(
~id, ~geometry,
"1", list(c(-119.036,23.097), c(-119.002,23.105), c(-119.010,23.136), c(-119.044,23.128), c(-119.036,23.097)),
"2", list(c(-119.002,23.105),c(-118.968,23.112),c(-118.977,23.143), c(-119.010,23.136), c(-119.002,23.105))
)
If possible, I'd like to do with dplyr commands.
out <- df %>%
group_by(id) %>%
summarize(geometry = list(Map(c, lon, lat)))
out
# # A tibble: 2 × 2
# id geometry
# <dbl> <list>
# 1 1 <list [5]>
# 2 2 <list [5]>
Comparison with your second frame (I named df2):
str(out)
# tibble [2 × 2] (S3: tbl_df/tbl/data.frame)
# $ id : num [1:2] 1 2
# $ geometry:List of 2
# ..$ :List of 5
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# ..$ :List of 5
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
str(df2)
# tibble [2 × 2] (S3: tbl_df/tbl/data.frame)
# $ id : chr [1:2] "1" "2"
# $ geometry:List of 2
# ..$ :List of 5
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# ..$ :List of 5
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1
# .. ..$ : num [1:2] -119 23.1