Change tags from a list column <-> columns for each key in wide format

Objects of classes osmapi_objects and osmapi_changesets can represent the tags in a column with a list with a data.frame for each row with 2 columns for keys and values, or by columns for each key. These functions allow to change the format of the tags.

Usage

tags_list2wide(x)

tags_wide2list(x)

Arguments

x

An osmapi_objects or osmapi_changesets objects as returned by, for example, osm_get_objects() or osm_get_changesets().

Value

A data frame with the same class and data than the original (osmapi_objects or osmapi_changesets) but with the specified tags' format.

Details

Both formats have advantages. Tags in a list of data.frames is a more compact representation and there is no risk of clashes of column names and tag keys. Tags in columns make it easier to select rows by tags as in a regular data.frame. Column name clashes are resolved and the original key names restored when transformed to tags list format.

By default, functions returning osmapi_objects or osmapi_changesets objects, use the the tags in a list column, but can return the results in a wide format using the parameter tags_in_columns = TRUE.

Examples

if (FALSE) {
peaks_wide <- osm_get_objects(
  osm_type = "nodes", osm_id = c(35308286, 1935675367), tags_in_columns = TRUE
)
peaks_list <- tags_wide2list(peaks_wide)

# tags in list format
peaks_list$tags

# Select peaks with `prominence` tag
peaks_wide[!is.na(peaks_wide$prominence), ]
peaks_list[sapply(peaks_list$tags, function(x) any(x$key == "prominence")), ]

cities_list <- osm_get_objects(osm_type = "relations", osm_id = c("40581", "341530"))
# Column name clash:
cities_wide <- tags_list2wide(cities_list)
}