st_join: spatial left or inner join

Description Usage Arguments Details Value Examples

View source: R/join.R

Description

spatial left or inner join

Usage

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st_join(x, y, join = st_intersects, FUN, suffix = c(".x", ".y"), ...,
  left = TRUE, largest = FALSE)

Arguments

x

object of class sf

y

object of class sf

join

geometry predicate function with the same profile as st_intersects; see details

FUN

deprecated;

suffix

length 2 character vector; see merge

...

arguments passed on to the join function (e.g. prepared, or a pattern for st_relate)

left

logical; if TRUE carry out left join, else inner join; see also left_join

largest

logical; if TRUE, return x features augmented with the fields of y that have the largest overlap with each of the features of x; see https://github.com/r-spatial/sf/issues/578

Details

alternative values for argument join are: st_disjoint st_touches st_crosses st_within st_contains st_overlaps st_covers st_covered_by st_equals or st_equals_exact, or user-defined functions of the same profile

Value

an object of class sf, joined based on geometry

Examples

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a = st_sf(a = 1:3,
 geom = st_sfc(st_point(c(1,1)), st_point(c(2,2)), st_point(c(3,3))))
b = st_sf(a = 11:14,
 geom = st_sfc(st_point(c(10,10)), st_point(c(2,2)), st_point(c(2,2)), st_point(c(3,3))))
st_join(a, b)
st_join(a, b, left = FALSE)
# two ways to aggregate y's attribute values outcome over x's geometries:
st_join(a, b) %>% aggregate(list(.$a.x), mean)
library(dplyr)
st_join(a, b) %>% group_by(a.x) %>% summarise(mean(a.y))
# example of largest = TRUE:
nc <- st_transform(st_read(system.file("shape/nc.shp", package="sf")), 2264)                
gr = st_sf(
    label = apply(expand.grid(1:10, LETTERS[10:1])[,2:1], 1, paste0, collapse = " "),
    geom = st_make_grid(nc))
gr$col = sf.colors(10, categorical = TRUE, alpha = .3)
# cut, to check, NA's work out:
gr = gr[-(1:30),]
nc_j <- st_join(nc, gr, largest = TRUE)
# the two datasets:
opar = par(mfrow = c(2,1), mar = rep(0,4))
plot(st_geometry(nc_j))
plot(st_geometry(gr), add = TRUE, col = gr$col)
text(st_coordinates(st_centroid(gr)), labels = gr$label)
# the joined dataset:
plot(st_geometry(nc_j), border = 'black', col = nc_j$col)
text(st_coordinates(st_centroid(nc_j)), labels = nc_j$label, cex = .8)
plot(st_geometry(gr), border = 'green', add = TRUE)
par(opar)

sf documentation built on July 24, 2019, 5:05 p.m.