我想创建一个数据集，其中包含不相交的多边形及其属性，以及当两个/所有多边形确实相交时的属性.
为了演示这个问题，我创建了一些虚构的数据
set.seed(131)
library(sf)
#create example data
m = rbind(c(0,0), c(1,0), c(1,1), c(0,1), c(0,0))
p = st_polygon(list(m))
n = 20
l = vector("list", n)
for (i in 1:n)
l[[i]] = p + 10 * runif(2)
s = st_sfc(l)
plot(s, col = sf.colors(categorical = TRUE, alpha = .5))
title("overlapping squares")
#convert to sf object
s <- st_as_sf(s)
#add some random info
s$tree_type <- rep(c("oak", "pine", "fir"), length.out=nrow(s))
which looks like this
数据是这样的:
Simple feature collection with 20 features and 1 field
Geometry type: POLYGON
Dimension: XY
Bounding box: xmin: 0.3840939 ymin: 1.132567 xmax: 10.19807 ymax: 10.14945
CRS: NA
First 10 features:
x tree_type
1 POLYGON ((2.06437 1.249422,... oak
2 POLYGON ((2.932732 3.757797... pine
3 POLYGON ((8.463468 5.292048... fir
4 POLYGON ((5.186254 2.378545... oak
5 POLYGON ((3.263181 9.149452... pine
6 POLYGON ((4.162483 3.446414... fir
7 POLYGON ((8.651544 3.160404... oak
8 POLYGON ((5.231186 2.916041... pine
9 POLYGON ((0.3840939 6.87075... fir
10 POLYGON ((7.742229 4.721718... oak
然后我像这样做一个self 交叉点
s_intersection <- st_intersection(s)
它创建了这样的数据
Simple feature collection with 31 features and 3 fields
Geometry type: GEOMETRY
Dimension: XY
Bounding box: xmin: 0.3840939 ymin: 1.132567 xmax: 10.19807 ymax: 10.14945
CRS: NA
First 10 features:
tree_type n.overlaps origins x
1 oak 1 1 POLYGON ((2.06437 1.249422,...
2 pine 1 2 POLYGON ((3.932732 4.757797...
3 fir 1 3 POLYGON ((8.463468 6.292048...
4 oak 1 4 POLYGON ((6.186254 2.378545...
5 pine 1 5 POLYGON ((3.263181 9.149452...
6 fir 1 6 POLYGON ((4.162483 3.446414...
7 oak 1 7 POLYGON ((9.651544 3.160404...
4.1 oak 2 4, 8 POLYGON ((6.186254 2.916041...
8 pine 1 8 MULTIPOLYGON (((5.826989 3....
9 fir 1 9 POLYGON ((0.3840939 6.87075...
我想要做的是用这两个多边形的属性替换列origins.因此，例如，多边形4.1将变为oak, pine.或者，如果它是在两列中，它是可以的.我想解决这个问题的方法是在origins列中取消列出观测，以便每个值都在自己的列中，然后将面的属性绑定到多个origins列中的每个值.但有没有更简单的方法呢？