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[英]R simulate spatial point data with points a maximum distance from previous point
[英]Spatial data: calculating the distance of points from the maximum point value and plotting
我的問題類似於計算每個點之間的距離的這篇文章。
就我而言,我希望找到每個點到具有最高值的點的距離。 我也想 plot 這種與lm()
的關系,但我正在努力用空間數據對象來完成這兩項任務。
我的數據不需要CRS,它是基於歐幾里得距離(因為這些點在一個房間里)。
以下數據的模擬示例,其中列variable
是感興趣的。
> dput(dat)
structure(list(date.hour = structure(c(1551057840, 1551057840,
1551057840, 1551057840, 1551057840, 1551057840, 1551057840), tzone = "UTC", class = c("POSIXct",
"POSIXt")), id = c(2, 5, 7, 8, 9, 10, 11), variable = c(456,
27, 130, 116, 92, 141, 145), xy_coord = c("6.2 14.8", "8.2 8.9",
"4.2 8.9", "2.2 8.9", "8.2 3.5", "6.2 3.5", "4.2 3.5")), row.names = c(NA,
-7L), groups = structure(list(id = c(2, 5, 7, 8, 9, 10, 11),
date.hour = structure(c(1551057840, 1551057840, 1551057840,
1551057840, 1551057840, 1551057840, 1551057840), tzone = "UTC", class = c("POSIXct",
"POSIXt")), .rows = structure(list(1L, 2L, 3L, 4L, 5L, 6L,
7L), ptype = integer(0), class = c("vctrs_list_of", "vctrs_vctr",
"list"))), row.names = c(NA, -7L), class = c("tbl_df", "tbl",
"data.frame"), .drop = TRUE), class = c("grouped_df", "tbl_df",
"tbl", "data.frame"))
> dat
# A tibble: 7 x 4
# Groups: id, date.hour [7]
date.hour id variable xy_coord
<dttm> <dbl> <dbl> <chr>
1 2019-02-25 01:24:00 2 456 6.2 14.8
2 2019-02-25 01:24:00 5 27 8.2 8.9
3 2019-02-25 01:24:00 7 130 4.2 8.9
4 2019-02-25 01:24:00 8 116 2.2 8.9
5 2019-02-25 01:24:00 9 92 8.2 3.5
6 2019-02-25 01:24:00 10 141 6.2 3.5
7 2019-02-25 01:24:00 11 145 4.2 3.5
>
使用sp()
package 將數據幀轉換為SpatialPointsDataFrame
:
#Split x and y to separate columns
dat$x <- sapply(strsplit(as.character(dat$xy_coord), " "), "[", 1); dat$x <- as.numeric(dat$x)
dat$y <- sapply(strsplit(as.character(dat$xy_coord), " "), "[", 2); dat$y <- as.numeric(dat$y)
#SpatialPointsDataFrame
coordinates(dat) <- ~x+y
這是我不知道要采取什么步驟的地方,但我想知道所有點到最高值的距離:
which.max(dat@data$variable)
然后 plot 這種關系與基礎plot()
。
如果我的問題不清楚,請告訴我。
我仍然不確定我是否理解您的問題,但我提出以下答案。
加載包
library(sf)
#> Linking to GEOS 3.9.1, GDAL 3.2.1, PROJ 7.2.1
library(tidyr)
加載數據
dat = structure(
list(
date.hour = structure(
c(
1551057840, 1551057840, 1551057840, 1551057840, 1551057840,
1551057840, 1551057840
),
tzone = "UTC",
class = c(
"POSIXct",
"POSIXt"
)
),
id = c(2, 5, 7, 8, 9, 10, 11),
variable = c(
456, 27, 130, 116, 92, 141, 145
),
xy_coord = c(
"6.2 14.8", "8.2 8.9", "4.2 8.9", "2.2 8.9", "8.2 3.5", "6.2 3.5",
"4.2 3.5"
)
),
row.names = c(NA,-7L),
groups = structure(
list(
id = c(2, 5, 7, 8, 9, 10, 11),
date.hour = structure(
c(
1551057840, 1551057840, 1551057840, 1551057840, 1551057840,
1551057840, 1551057840
),
tzone = "UTC",
class = c(
"POSIXct",
"POSIXt"
)
),
.rows = structure(
list(1L, 2L, 3L, 4L, 5L, 6L, 7L),
ptype = integer(0),
class = c(
"vctrs_list_of", "vctrs_vctr", "list"
)
)
),
row.names = c(NA, -7L),
class = c("tbl_df", "tbl", "data.frame"),
.drop = TRUE
),
class = c("grouped_df", "tbl_df", "tbl", "data.frame")
)
分離xy_coord
列,將列轉換為數字並創建一個 sf object
dat_sf <- st_as_sf(
separate(dat, xy_coord, c("x", "y"), sep = " ", convert = TRUE),
coords = c("x", "y")
)
找到變量的最大值
which.max(dat_sf[["variable"]])
#> [1] 1
計算所有距離
dat_sf[["distances"]] <- st_distance(dat_sf, dat_sf[1, ])
Plot
plot(variable ~ distances, data = dat_sf)
由代表 package (v2.0.1) 於 2021 年 11 月 22 日創建
您還可以刪除第一個點(距離 = 0)。
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