spatial - 用箭头连接两组 sfc 点
问题描述
我有一个数据框,其中两列是 sfc 点列表。
> head(moves)
hiring start end
1 1 POINT (-2.030474 51.36306) POINT (-2.250102 51.41609)
2 2 POINT (-2.319776 51.46162) POINT (-2.491189 51.41029)
3 4 POINT (-2.025846 51.47712) POINT (-2.063781 51.49158)
4 6 POINT (-2.426711 51.38076) POINT (-2.132722 51.46999)
5 7 POINT (-2.116654 51.4887) POINT (-2.204403 51.51874)
6 8 POINT (-2.122917 51.5861) POINT (-2.134635 51.51806)
我需要逐行从一个点到另一个点画线(理想情况下,指向)。我的问题似乎是我的文件(移动)不是 sf 对象。我需要制作一个,还是将其中的数据转换为其他格式?
> dput(head(moves))
structure(list(hiring = c(1L, 2L, 4L, 6L, 7L, 8L), start = list(
structure(c(-2.03047447566941, 51.3630641761757), class = c("XY",
"POINT", "sfg")), structure(c(-2.31977575385362, 51.4616210429381
), class = c("XY", "POINT", "sfg")), structure(c(-2.02584648038463,
51.4771163047678), class = c("XY", "POINT", "sfg")),
structure(c(-2.42671091326068,
51.3807643595824), class = c("XY", "POINT", "sfg")),
structure(c(-2.1166538974769,
51.4887039877758), class = c("XY", "POINT", "sfg")),
structure(c(-2.12291705783767,
51.5860957106472), class = c("XY", "POINT", "sfg"))), end = list(
structure(c(-2.25010169528537, 51.4160891285008), class = c("XY",
"POINT", "sfg")), structure(c(-2.49118920138511, 51.4102939905029
), class = c("XY", "POINT", "sfg")), structure(c(-2.06378098244424,
51.491583244303), class = c("XY", "POINT", "sfg")),
structure(c(-2.13272163343155,
51.469987047928), class = c("XY", "POINT", "sfg")),
structure(c(-2.20440279315621,
51.5187438721622), class = c("XY", "POINT", "sfg")),
structure(c(-2.1346350057738,
51.5180564842074), class = c("XY", "POINT", "sfg")))), row.names = c(NA,
6L), class = "data.frame")
解决方案
在空白背景上带有基本图形的简单箭头(无地图)。
编辑:使用原始帖子中现在给出的数据,我意识到这不是对象,moves$start
而只是对象列表。它们可以变成对象,然后可以提取坐标。完整代码是:moves$end
sfc
sfg
sfc
sf::st_as_sfc
library(sf)
#> Linking to GEOS 3.8.0, GDAL 3.0.4, PROJ 6.3.1
moves <- structure(
list(hiring = c(1L, 2L, 4L, 6L, 7L, 8L),
start = list(
structure(c(-2.03047447566941, 51.3630641761757),
class = c("XY", "POINT", "sfg")),
structure(c(-2.31977575385362, 51.4616210429381),
class = c("XY", "POINT", "sfg")),
structure(c(-2.02584648038463, 51.4771163047678),
class = c("XY", "POINT", "sfg")),
structure(c(-2.42671091326068, 51.3807643595824),
class = c("XY", "POINT", "sfg")),
structure(c(-2.1166538974769, 51.4887039877758),
class = c("XY", "POINT", "sfg")),
structure(c(-2.12291705783767, 51.5860957106472),
class = c("XY", "POINT", "sfg"))),
end = list(
structure(c(-2.25010169528537, 51.4160891285008),
class = c("XY", "POINT", "sfg")),
structure(c(-2.49118920138511, 51.4102939905029),
class = c("XY", "POINT", "sfg")),
structure(c(-2.06378098244424, 51.491583244303),
class = c("XY", "POINT", "sfg")),
structure(c(-2.13272163343155, 51.469987047928),
class = c("XY", "POINT", "sfg")),
structure(c(-2.20440279315621, 51.5187438721622),
class = c("XY", "POINT", "sfg")),
structure(c(-2.1346350057738, 51.5180564842074),
class = c("XY", "POINT", "sfg")))),
w.names = c(NA, 6L), class = "data.frame")
co_s <- st_coordinates(st_as_sfc(moves$start))
co_e <- st_coordinates(st_as_sfc(moves$end))
s_lon <- co_s[,"X"]
s_lat <- co_s[,"Y"]
e_lon <- co_e[,"X"]
e_lat <- co_e[,"Y"]
plot(c(s_lon, e_lon), c(s_lat, e_lat), col = rep(c("red", "blue"), each = 6),
pch = 20, cex = 2, xlab = "lon", ylab = "lat")
arrows(s_lon, s_lat, e_lon, e_lat)
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