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.
filter_by_sf(gtfs, geom, spatial_operation = sf::st_intersects, keep = TRUE)A GTFS object, as created by read_gtfs().
An sf object. Describes the geometry used to filter the data.
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.
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).
The GTFS object passed to the gtfs parameter, after the filtering
process.
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()
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)
#> 860808 bytes
# keeps entries that intersect with the specified polygon
smaller_gtfs <- filter_by_sf(gtfs, bbox)
object.size(smaller_gtfs)
#> 324952 bytes
# drops entries that intersect with the specified polygon
smaller_gtfs <- filter_by_sf(gtfs, bbox, keep = FALSE)
object.size(smaller_gtfs)
#> 512288 bytes
# uses a different function to filter the gtfs
smaller_gtfs <- filter_by_sf(gtfs, bbox, spatial_operation = sf::st_contains)
object.size(smaller_gtfs)
#> 68976 bytes