get_trails_osm: Get accessible trails from OpenStreetMap

In ecological-cities/home2park: Spatial Provision of Urban Parks

Get accessible trails from OpenStreetMap

Description

Download and process OpenStreetMap (OSM) accessible trail (lines) within place, from the Geofabrik database. It is a wrapper around functions in the package osmextract, and processes the downloaded files for subsequent analyses. Refer to package osmextract for more details and options for input arguments when downloading the data.

Usage

get_trails_osm(
  place,
  date = NULL,
  dir_raw = osmextract::oe_download_directory(),
  filename = NULL,
  ...
)

Arguments

place	sf object (with projected coordinate reference system). Geographical area to match with the (.osm.pbf) file in the data archive. Argument passed to osmextract::oe_match().
date	Date of OSM data snapshot to download. Object of class "Date" in format ⁠%Y-%m-%d⁠. Refer to https://download.geofabrik.de for the specific dates available. Defaults to NULL (download the latest available data).
dir_raw	character. Directory to download the raw unprocessed OSM data. Passed to argument download_directory in osmextract::oe_read().
filename	character (optional). File path to export output data (GeoJSON format).
...	Other arguments passed to osmextract::oe_read().

Details

OSM lines filtered by key-value attributes, where ⁠highway:⁠ is track, path, footway or cycleway, and ⁠access:⁠ is not no or private.

Value

The processed trail lines (sf object).

Examples

## Not run: 
data(pop_sgp)
pop_sgp <- sf::st_transform(pop_sgp, sf::st_crs(32648)) # transform to projected crs

# merge all census blocks for chosen year (2020) into single multi-polygon
# function requires that polygons are merged
city_boundaries <- pop_sgp %>%
   dplyr::filter(year == 2020) %>%
   sf::st_union() %>%
   sf::st_as_sf() %>%
   smoothr::fill_holes(threshold = units::set_units(1, 'km^2'))  %>% # clean up
   smoothr::drop_crumbs(threshold = units::set_units(1, 'km^2'))  %>%
   sf::st_make_valid()

# run function
get_trails_osm(place = city_boundaries,
               date = as.Date('2021-01-01'),
               filename = 'accessible-trails_osm-lines_2021-01-01.geojson')

## End(Not run)

ecological-cities/home2park documentation built on Dec. 6, 2023, 1:05 a.m.