ohsome_extract_elements {ohsome}

Extract OSM elements

Description

Create an ohsome_query object for OSM element extraction

Usage

ohsome_extract_elements(
  boundary = NULL,
  geometryType = c("centroid", "bbox", "geometry"),
  time = NULL,
  properties = NULL,
  clipGeometry = TRUE,
  ...
)

ohsome_elements_bbox(boundary = NULL, ...)

ohsome_elements_centroid(boundary = NULL, ...)

ohsome_elements_geometry(boundary = NULL, ...)

Arguments

boundary

Bounding geometries specified by WGS84 coordinates in the order ⁠lon,lat⁠. The geometries of sf are transformed to WGS84 if the CRS of the object is known. The following classes are supported:

• sf with (MULTI)POLYGON geometries

• sfc with (MULTI)POLYGON geometries

• sfg with (MULTI)POLYGON geometries and WGS 84 coordinates

• bbox created with sf::st_bbox() or tmaptools::bb()

• matrix created with sp::bbox() or osmdata::getbb()

• character providing textual definitions of bounding polygons, boxes or circles as allowed by the ohsome API (see ohsome API - Boundaries ):

  • bboxes: WGS84 coordinates in the following format: "id1:lon1,lat1,lon2,lat2|id2:lon1,lat1,lon2,lat2|..." OR "lon1,lat1,lon2,lat2|lon1,lat1,lon2,lat2|..."

  • bcircles: WGS84 coordinates + radius in meter in the following format: "id1:lon,lat,r|id2:lon,lat,r|..." OR "lon,lat,r|lon,lat,r|..."

  • bpolys: WGS84 coordinates given as a list of coordinate pairs (as for bboxes) or GeoJSON FeatureCollection. The first point has to be the same as the last point and MultiPolygons are only supported in GeoJSON.

• list of bbox, matrix or character. Bounding geometry types of all list elements must be the same. Does not work with GeoJSON FeatureCollections.

geometryType

character; type of geometry to be extracted:

• "centroid",

• "bboxes" (bounding boxes), or

• "geometry"

Caveat: Node elements are omitted from results in queries for bounding boxes.

time

character; time parameter of the query (see Supported time formats).

properties

character; properties to be extracted with the features:

• "tags", and/or

• "metadata" (i.e. ⁠@changesetId⁠, ⁠@lastEdit⁠, ⁠@osmType⁠, and ⁠@version⁠)

Multiple values can be provided as comma-separated character or as character vector. This defaults to NULL (provides ⁠@osmId⁠).

clipGeometry

logical; specifies whether the returned geometries should be clipped to the query’s spatial boundary

...

Parameters of the request to the ohsome API endpoint.

Details

ohsome_extract_elements() creates an ohsome_query object for OSM element extraction. ohsome_elements_bbox(), ohsome_elements_centroid() and ohsome_elements_geometry() are wrapper functions for specific elements extraction endpoints. Boundary objects are passed via set_boundary() into ohsome_boundary().

Value

An ohsome_query object. The object can be sent to the ohsome API with ohsome_post(). It consists of the following elements:

• url: The URL of the endpoint.

• encode: The way the information is encoded and then posted to the ohsome API. Set as "form".

• body: The parameters of the query such as format, filter or bpolys.

See Also

ohsome API Endpoints – Elements Extraction

Examples

# Extract geometries, metadata and tags of man-made objects around "Null Island":
ohsome_elements_geometry(
    "0,0,10", 
    filter = "man_made=*", 
    time = "2022-01-01",
    properties = c("metadata", "tags")
)