opq: Build an Overpass query
In osmdata: Import 'OpenStreetMap' Data as Simple Features or Spatial Objects

Description Usage Arguments Value Note Examples

Build an Overpass query

opq(
  bbox = NULL,
  nodes_only = FALSE,
  datetime = NULL,
  datetime2 = NULL,
  timeout = 25,
  memsize
)

`bbox`	Either (i) four numeric values specifying the maximal and minimal longitudes and latitudes, in the form `c(xmin, ymin, xmax, ymax)` or (ii) a character string in the form `xmin,ymin,xmax,ymax`. These will be passed to getbb to be converted to a numerical bounding box. Can also be (iii) a matrix representing a bounding polygon as returned from `getbb(..., format_out = "polygon")`.
`nodes_only`	If `TRUE`, query OSM nodes only. Some OSM structures such as `place = "city"` or `highway = "traffic_signals"` are represented by nodes only. Queries are built by default to return all nodes, ways, and relation, but this can be very inefficient for node-only queries. Setting this value to `TRUE` for such cases makes queries more efficient, with data returned in the `osm_points` list item.
`datetime`	If specified, a date and time to extract data from the OSM database as it was up to the specified date and time, as described at https://wiki.openstreetmap.org/wiki/Overpass_API/Overpass_QL#date. This must be in ISO8601 format ("YYYY-MM-DDThh:mm:ssZ"), where both the "T" and "Z" characters must be present.
`datetime2`	If specified, return the difference in the OSM database between `datetime` and `datetime2`, where `datetime2 > datetime`. See https://wiki.openstreetmap.org/wiki/Overpass_API/Overpass_QL#Delta_between_two_dates_.28.22diff.22.29.
`timeout`	It may be necessary to increase this value for large queries, because the server may time out before all data are delivered.
`memsize`	The default memory size for the 'overpass' server in bytes; may need to be increased in order to handle large queries.

An overpass_query object

See https://wiki.openstreetmap.org/wiki/Overpass_API#Resource_management_options_.28osm-script.29 for explanation of timeout and memsize (or maxsize in overpass terms). Note in particular the comment that queries with arbitrarily large memsize are likely to be rejected.

## Not run: 
q <- getbb ("portsmouth", display_name_contains = "United States") %>%
            opq () %>%
            add_osm_feature("amenity", "restaurant") %>%
            add_osm_feature("amenity", "pub")
osmdata_sf (q) # all objects that are restaurants AND pubs (there are none!)
q1 <- getbb ("portsmouth", display_name_contains = "United States") %>%
                opq () %>%
                add_osm_feature("amenity", "restaurant")
q2 <- getbb ("portsmouth", display_name_contains = "United States") %>%
                opq () %>%
                add_osm_feature("amenity", "pub")
c (osmdata_sf (q1), osmdata_sf (q2)) # all restaurants OR pubs

# Use nodes_only to retrieve single point data only, such as for central
# locations of cities.
opq <- opq (bbox, nodes_only = TRUE) %>%
    add_osm_feature (key = "place", value = "city") %>%
    osmdata_sf (quiet = FALSE)

## End(Not run)