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Clean the oneway values in a OSM network

Source: R/get-network-graph.R
clean_oneway.Rd

This helper function standardises the oneway values in a OSM network. It also applies a few implied oneway tag restriction based on the junction tag values if specified and substitutes remaining NA values as "no". See Details.

Usage

clean_oneway(x, quiet = FALSE)

Arguments

x

a sf object representing a spatial network with the oneway and junction columns

quiet

logical, whether to suppress messages. Default is FALSE.

Value

An sf object with standardised oneway values

Details

According to the information reported at wiki.openstreetmap.org, the oneway key can only assume one out of 5 possible values: "yes", "no", "-1", "reversible", and "alternating". However, the oneway tag is optional and typically missing. Hence, the objective of this function is to replace the NA values whenever possible using contextual information.

In fact, there are tags or combination of tags (such as junction='roundabout') which imply oneway='yes'. This function tests such combination and converts the NA values into 'yes'.

Then, the oneway='-1' values (which indicate wrong-way roads) are fixed by reversing the geometry of the lines and setting the road as oneway.

Finally, the remaining NA values are set as oneway='no'. For simplicity, even the oneway='reversible' and oneway='alternating' are converted into oneway='no'.

Examples

# Copy the ITS file to tempdir() to make sure that the examples do not
# require internet connection. You can skip the next 4 lines (and start
# directly with oe_get_keys) when running the examples locally.
its_pbf = file.path(tempdir(), "test_its-example.osm.pbf")
file.copy(
  from = system.file("its-example.osm.pbf", package = "osmextract"),
  to = its_pbf,
  overwrite = TRUE
)
#> [1] TRUE
roads <- oe_get_network(
  place = "ITS Leeds",
  mode = "driving",
  download_directory = tempdir(),
  quiet = TRUE
)
table(roads$oneway, useNA = "ifany")
#> 
#>  yes <NA> 
#>   13   80 
roads_clean <- clean_oneway(roads)
table(roads_clean$oneway, useNA = "ifany")
#> 
#>  no yes 
#>  80  13