Convert between simple feature and data frame objects

Helper function to convert a simple feature object to data frame by dropping geometry, converting geometry to well known text, or (if the geometry type is not POINT) getting coordinates for a centroid or point on surface. If an sfc object is provided,the "drop" geometry option is not supported.

Usage

sf_to_df(
  x,
  crs = 4326,
  coords = c("lon", "lat"),
  geometry = "centroid",
  keep_all = TRUE
)

df_to_sf(
  x,
  crs = NULL,
  coords = c("lon", "lat"),
  from_crs = 4326,
  into = NULL,
  sep = ",",
  rev = TRUE,
  remove_coords = FALSE,
  geo = FALSE,
  address = "address"
)

check_coords(x = NULL, coords = NULL, default = c("lon", "lat"), rev = FALSE)

has_coords(x, coords = NULL, value = TRUE)

Arguments

x: A sf or sfc object or a data frame with lat/lon coordinates in a single column or two separated columns.
crs: Cordinate reference system to return, Default: 4326 for sf_to_df and NULL for df_to_sf
coords: Coordinate columns for input dataframe or output sf object (if geometry is 'centroid' or 'point') Default: c("lon", "lat").
geometry: Type of geometry to include in data frame. options include "drop", "wkt", "centroid", "point", Default: 'centroid'.
keep_all: If FALSE, drop all columns other than those named in coords, Default: TRUE.
from_crs: For df_to_sf, coordinate reference system used by coordinates or well known text in data frame.
into: If coords is a single column name with both longitude and latitude, into is used as the names of the new columns that coords is separated into. Passed to tidyr::separate.
sep: If coords is a single column name with both longitude and latitude, sep is used as the separator between coordinate values. Passed to tidyr::separate.
rev: If TRUE, reverse c("lat", "lon") coords to c("lon", "lat"). check_coords only.
remove_coords: For df_to_sf, if TRUE, remove the coordinate columns after converting a data frame to simple feature object; defaults to FALSE.
geo: If TRUE, use address_to_sf to geocode address column; defaults to FALSE.
address: Address column name passed to tidygeocoder::geocode or tidygeocoder::geo
default: c("lon", "lat").
value: If TRUE, return the value of the coordinate column names. Used by has_coords.

Value

sf_to_df() returns a data frame with geometry dropped or converted to wkt or coordinates for the centroid or point on surface; df_to_sf()returns a simple feature object with POINT geometry.

Details

check_coords() is a helper function used by df_to_sf() to suggest the appropriate coordinate column names based on the column names in the provided data frame.

Examples

nc <- read_sf_path(system.file("shape/nc.shp", package = "sf"))

# Convert a sf object to a data frame
nc_df <- sf_to_df(nc)

# Convert a data frame to a sf object
df_to_sf(nc_df, coords = c("lon", "lat"), remove_coords = TRUE)
#> Simple feature collection with 100 features and 14 fields
#> Attribute-geometry relationship: 14 constant, 0 aggregate, 0 identity
#> Geometry type: POINT
#> Dimension:     XY
#> Bounding box:  xmin: -84.05976 ymin: 34.07684 xmax: -75.80916 ymax: 36.49119
#> Geodetic CRS:  WGS 84
#> # A tibble: 100 × 15
#>     AREA PERIMETER CNTY_ CNTY_ID NAME  FIPS  FIPSNO CRESS_ID BIR74 SID74 NWBIR74
#>  * <dbl>     <dbl> <dbl>   <dbl> <chr> <chr>  <dbl>    <int> <dbl> <dbl>   <dbl>
#>  1 0.114      1.44  1825    1825 Ashe  37009  37009        5  1091     1      10
#>  2 0.061      1.23  1827    1827 Alle… 37005  37005        3   487     0      10
#>  3 0.143      1.63  1828    1828 Surry 37171  37171       86  3188     5     208
#>  4 0.07       2.97  1831    1831 Curr… 37053  37053       27   508     1     123
#>  5 0.153      2.21  1832    1832 Nort… 37131  37131       66  1421     9    1066
#>  6 0.097      1.67  1833    1833 Hert… 37091  37091       46  1452     7     954
#>  7 0.062      1.55  1834    1834 Camd… 37029  37029       15   286     0     115
#>  8 0.091      1.28  1835    1835 Gates 37073  37073       37   420     0     254
#>  9 0.118      1.42  1836    1836 Warr… 37185  37185       93   968     4     748
#> 10 0.124      1.43  1837    1837 Stok… 37169  37169       85  1612     1     160
#> # … with 90 more rows, and 4 more variables: BIR79 <dbl>, SID79 <dbl>,
#> #   NWBIR79 <dbl>, geometry <POINT [°]>

# If lon and lat values are present in a single column, use the into parameter
# to split the values back into separate columns
nc_df$xy <- paste(nc_df$lon, nc_df$lat, sep = ",")

df_to_sf(nc_df, coords = "xy", into = c("lon", "lat"))
#> Simple feature collection with 100 features and 16 fields
#> Attribute-geometry relationship: 16 constant, 0 aggregate, 0 identity
#> Geometry type: POINT
#> Dimension:     XY
#> Bounding box:  xmin: -84.05976 ymin: 34.07684 xmax: -75.80916 ymax: 36.49119
#> Geodetic CRS:  WGS 84
#> # A tibble: 100 × 17
#>     AREA PERIMETER CNTY_ CNTY_ID NAME  FIPS  FIPSNO CRESS_ID BIR74 SID74 NWBIR74
#>  * <dbl>     <dbl> <dbl>   <dbl> <chr> <chr>  <dbl>    <int> <dbl> <dbl>   <dbl>
#>  1 0.114      1.44  1825    1825 Ashe  37009  37009        5  1091     1      10
#>  2 0.061      1.23  1827    1827 Alle… 37005  37005        3   487     0      10
#>  3 0.143      1.63  1828    1828 Surry 37171  37171       86  3188     5     208
#>  4 0.07       2.97  1831    1831 Curr… 37053  37053       27   508     1     123
#>  5 0.153      2.21  1832    1832 Nort… 37131  37131       66  1421     9    1066
#>  6 0.097      1.67  1833    1833 Hert… 37091  37091       46  1452     7     954
#>  7 0.062      1.55  1834    1834 Camd… 37029  37029       15   286     0     115
#>  8 0.091      1.28  1835    1835 Gates 37073  37073       37   420     0     254
#>  9 0.118      1.42  1836    1836 Warr… 37185  37185       93   968     4     748
#> 10 0.124      1.43  1837    1837 Stok… 37169  37169       85  1612     1     160
#> # … with 90 more rows, and 6 more variables: BIR79 <dbl>, SID79 <dbl>,
#> #   NWBIR79 <dbl>, lon <dbl>, lat <dbl>, geometry <POINT [°]>