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Combine separate coordinate columns into one

Source: R/latlong_combine.R
latlong_combine.Rd

Merges separate latitude and longitude columns into a single combined coordinate column, appended to the data frame. The inverse of this operation is latlong_split. Note that combined columns are not accepted by the functions latlong_range and latlong_region; use latlong_split to separate columns again before filtering.

Usage

latlong_combine(
  data,
  latitude,
  longitude,
  new_column = "latlong",
  sep = ", ",
  drop_na = FALSE
)

Arguments

data

A data frame containing coordinate columns.

latitude

Column name of the latitude column, supplied either unquoted (lat) or quoted ("lat"). Required if combined_col is not provided.

longitude

Column name of the longitude column, supplied either unquoted (lon) or quoted ("lon"). Required if combined_col is not provided.

new_column

Column name for the new combined column, supplied either unquoted (latlong) or quoted ("latlong"). Default is latlong.

sep

Character. Separator inserted between latitude and longitude values in the combined column. Default is ", ". Must match the sep argument of latlong_split if the combined column will be split again later.

drop_na

Logical. If TRUE, rows where either the latitude or longitude column is NA are dropped before combining. Default is FALSE.

Value

The input data frame with one additional character column appended, named according to new_column, containing values of the form "<latitude><sep><longitude>". The original latitude and longitude columns are retained. If drop_na = FALSE, rows with NA in either coordinate column will produce "NA<sep>NA" or "<value><sep>NA" in the combined column.

Details

Both coordinate columns are coerced to character before concatenation via paste0(), so numeric, integer, and character coordinate columns are all accepted. No validation of coordinate ranges or formats is performed; use latlong_format to check column formats before combining.

A console message reports the number of rows removed when drop_na = TRUE.

See also

latlong_split for splitting a combined coordinate column back into separate latitude and longitude columns,

latlong_format for checking coordinate formats before combining.

Examples

df <- data.frame(
  id  = 1:4,
  lat = c(51.5, 48.8, 40.7, 35.6),
  lon = c(-0.1, 2.3, -74.0, 139.7)
)

# Combine with default separator and column name
latlong_combine(df, latitude = lat, longitude = lon)
#>   id  lat   lon     latlong
#> 1  1 51.5  -0.1  51.5, -0.1
#> 2  2 48.8   2.3   48.8, 2.3
#> 3  3 40.7 -74.0   40.7, -74
#> 4  4 35.6 139.7 35.6, 139.7

# Use a custom separator and column name
latlong_combine(df, latitude = lat, longitude = lon,
                new_column = coords, sep = ";")
#>   id  lat   lon     coords
#> 1  1 51.5  -0.1  51.5;-0.1
#> 2  2 48.8   2.3   48.8;2.3
#> 3  3 40.7 -74.0   40.7;-74
#> 4  4 35.6 139.7 35.6;139.7

# Drop rows where either coordinate is NA
df_na <- data.frame(
  lat = c(51.5, NA, 40.7),
  lon = c(-0.1, 2.3, NA)
)
latlong_combine(df_na, latitude = lat, longitude = lon, drop_na = TRUE)
#> [latlong_combine] 2 NA row(s) removed
#>    lat  lon    latlong
#> 1 51.5 -0.1 51.5, -0.1