galah (version 1.5.4)

galah_polygon: Narrow a query to within a specified polygon

Description

Restrict results to those from a specified area. Areas must be polygons. Polygons must be supplied as an sf object, a 'well-known text' (WKT) string, or a shapefile. Polygons and shapefiles must not be overly complex (i.e. have too many characters or too many vertices) or they will not be accepted in a query to the ALA.

Usage

galah_polygon(...)
# S3 method for data_request
st_crop(x, y, ...)

Value

length-1 object of class character and galah_geolocate, containing a multipolygon WKT string representing the area provided.

Arguments

...

When supplied to galah_polygon(), a single sf object, WKT string or shapefile. Currently ignored when supplied to st_crop.data_request()

x

An object of class data_request, created using galah_call()

y

A single sf object, WKT string or shapefile

Details

WKT strings longer than 10000 characters and sf objects with more than 500 vertices will not be accepted by the ALA. Some polygons may need to be simplified.

See Also

galah_bbox() & galah_geolocate() for other ways to narrow queries by location. search_taxa(), galah_filter() and galah_select() for other ways to restrict the information returned by atlas_occurrences() and related functions.

Examples

if (FALSE) {
# Search for records within a polygon using an `sf` object
location <- "POLYGON((142.3 -29.0,142.7 -29.1,142.7 -29.4,142.3 -29.0))" |>
  sf::st_as_sfc()
galah_call() |>
  galah_identify("reptilia") |>
  galah_polygon(location) |>
  atlas_counts()

# Search for records using a shapefile
galah_config(email = "your_email_here")
location <- galah_geolocate(sf::st_read(path/to/shapefile.shp))
galah_call() |>
  galah_identify("vulpes") |>
  galah_polygon(location) |>
  atlas_occurrences()

# Search for records using a Well-known Text string (WKT)
wkt <- "POLYGON((142.3 -29.0,142.7 -29.1,142.7 -29.4,142.3 -29.0))"
galah_call() |>
  galah_identify("vulpes") |>
  galah_polygon(wkt) |>
  atlas_counts()
}