如何从多面转换为空间多边形数据框

How do you convert from a MULTIPOLYGON to a SpatialPolygonsDataFrame in R?

如何从R中的MULTIPOLYGON转换为SpatialPolygonsDataFrame?

I can't find any other resources online and I attempted to discretise the same file that was a GEOMETRYCOLLECTION, XY and sfg class, however, this led to a continuous loop of referencing the same polygon without accessing the individual points. I'm happy to provide any additional clarification and will appreciate any insight.

我在网上找不到任何其他资源,我试图对同一个GEOMETRYCOLLECTION,XY和sfg类的文件进行离散化,但是,这导致了连续循环引用相同的多边形而不访问各个点。我很乐意提供任何额外的澄清,并将欣赏任何见解。

A sample of one of the outputs for the multipolygon Ref_circles to show formatting is given as:

多面体Ref_circles的一个输出样本显示格式,如下所示:

Ref_circles[1]
[[1]]
[[1]][[1]]
       [,1]     [,2]
[1,] 51.62730 4.340600
[2,] 51.62549 4.343550
[3,] 51.61800 4.357353
[4,] 51.61124 4.371529
[5,] 51.60523 4.386039
[6,] 51.59998 4.400845
...
[311,] 51.63570 4.322473
[312,] 51.62894 4.336649
[313,] 51.62730 4.340600

1 个解决方案

#1

My first question to you would be: why do you want to convert from an sf object (MULTIPOLYGON) to an sp object (SpatialPolygonDataFrame), as sf super-seeds sp?

我的第一个问题是:为什么你想从sf对象(MULTIPOLYGON)转换为sp对象(SpatialPolygonDataFrame),作为sf super-seeds sp?

There are probably ways to achieve your end goal staying within the sf library without having to do this conversion.

可能有一些方法可以实现最终目标,无需进行此转换即可保留在sf库中。

If you still want to do it, it will be along the lines of

如果你仍然想要这样做,那将是一致的

library(sf)
library(sp)

## using a MULTIPOLYGON data set supplied with library(sf)
nc <- sf::st_read(system.file("shape/nc.shp", package="sf"))

## convert the geometry of the `sf` object to SpatialPolygons
spd <- sf::as_Spatial(st_geometry(nc), IDs = as.character(1:nrow(nc)))

class(spd)
# [1] "SpatialPolygons"
# attr(,"package")
# [1] "sp"

## grab the data from the sf object
df <- nc
df$geometry <- NULL
df <- as.data.frame(df)

## create the SpatialPolygonsDataFrame
spd <- sp::SpatialPolygonsDataFrame(spd, data = df)

class(spd)
# [1] "SpatialPolygonsDataFrame"
# attr(,"package")
# [1] "sp"

head(spd@data)
# AREA PERIMETER CNTY_ CNTY_ID        NAME  FIPS FIPSNO CRESS_ID BIR74 SID74 NWBIR74 BIR79 SID79 NWBIR79
# 1 0.114     1.442  1825    1825        Ashe 37009  37009        5  1091     1      10  1364     0      19
# 2 0.061     1.231  1827    1827   Alleghany 37005  37005        3   487     0      10   542     3      12
# 3 0.143     1.630  1828    1828       Surry 37171  37171       86  3188     5     208  3616     6     260
# 4 0.070     2.968  1831    1831   Currituck 37053  37053       27   508     1     123   830     2     145
# 5 0.153     2.206  1832    1832 Northampton 37131  37131       66  1421     9    1066  1606     3    1197
# 6 0.097     1.670  1833    1833    Hertford 37091  37091       46  1452     7     954  1838     5    1237

#1