auk_distance {auk}

Filter eBird data by distance travelled

Description

Define a filter for the eBird Basic Dataset (EBD) based on the distance travelled on the checklist. This function only defines the filter and, once all filters have been defined, auk_filter() should be used to call AWK and perform the filtering. Note that stationary checklists (i.e. point counts) have no distance associated with them, however, since these checklists can be assumed to have 0 distance they will be kept if 0 is in the range defined by distance.

Usage

auk_distance(x, distance, distance_units)

Arguments

x

auk_ebd or auk_sampling object; reference to file created by auk_ebd() or auk_sampling().

distance

integer; 2 element vector specifying the range of distances to filter by. The default is to accept distances in kilometers, use distance_units = "miles" for miles.

distance_units

character; whether distances are provided in kilometers (the default) or miles.

Details

This function can also work with on an auk_sampling object if the user only wishes to filter the sampling event data.

Value

An auk_ebd object.

See Also

Other filter: auk_bbox(), auk_bcr(), auk_breeding(), auk_complete(), auk_country(), auk_county(), auk_date(), auk_duration(), auk_exotic(), auk_extent(), auk_filter(), auk_last_edited(), auk_observer(), auk_project(), auk_protocol(), auk_species(), auk_state(), auk_time(), auk_year()

Examples

# only keep checklists that are less than 10 km long
system.file("extdata/ebd-sample.txt", package = "auk") %>%
  auk_ebd() %>%
  auk_distance(distance = c(0, 10))
  
# alternatively, without pipes
ebd <- auk_ebd(system.file("extdata/ebd-sample.txt", package = "auk"))
auk_distance(ebd, distance = c(0, 10))