filter_by_sf: Filter a GTFS object using a simple features object

In gtfstools: General Transit Feed Specification (GTFS) Editing and Analysing Tools

Filter a GTFS object using a simple features object

Description

Filters a GTFS object using the geometry of an sf object, keeping (or dropping) entries related to shapes and trips selected through a spatial operation.

Usage

filter_by_sf(gtfs, geom, spatial_operation = sf::st_intersects, keep = TRUE)

Arguments

gtfs	A GTFS object, as created by read_gtfs().
geom	An sf object. Describes the geometry used to filter the data.
spatial_operation	A spatial operation function from the set of options listed in geos_binary_pred (check the DE-I9M Wikipedia entry for the definition of each function). Defaults to sf::st_intersects, which tests if the shapes and trips have ANY intersection with the object specified in geom. Please note that geom is passed as the x argument of these functions.
keep	A logical. Whether the entries related to the shapes and trips that cross through the given geometry should be kept or dropped (defaults to TRUE, which keeps the entries).

Value

The GTFS object passed to the gtfs parameter, after the filtering process.

See Also

Other filtering functions: filter_by_agency_id(), filter_by_route_id(), filter_by_route_type(), filter_by_service_id(), filter_by_shape_id(), filter_by_stop_id(), filter_by_time_of_day(), filter_by_trip_id(), filter_by_weekday()

Examples

data_path <- system.file("extdata/spo_gtfs.zip", package = "gtfstools")
gtfs <- read_gtfs(data_path)

shape_id <- "68962"
shape_sf <- convert_shapes_to_sf(gtfs, shape_id)
bbox <- sf::st_bbox(shape_sf)
object.size(gtfs)

# keeps entries that intersect with the specified polygon
smaller_gtfs <- filter_by_sf(gtfs, bbox)
object.size(smaller_gtfs)

# drops entries that intersect with the specified polygon
smaller_gtfs <- filter_by_sf(gtfs, bbox, keep = FALSE)
object.size(smaller_gtfs)

# uses a different function to filter the gtfs
smaller_gtfs <- filter_by_sf(gtfs, bbox, spatial_operation = sf::st_contains)
object.size(smaller_gtfs)

gtfstools documentation built on Nov. 24, 2022, 5:09 p.m.