Filter a collection of place names by various criteria

A data frame of place names can be filtered according to name, geographic location, feature type, or other criteria. All text-related matches are by default treated as regular expressions and are case-insensitive: you can change this behaviour via the ignore_case and as_regex parameters.

Usage

an_filter(
  gaz,
  query,
  feature_ids,
  extent,
  feature_type,
  origin,
  origin_gazetteer,
  ignore_case = TRUE,
  as_regex = TRUE
)

Arguments

gaz

data.frame or SpatialPointsDataFrame: as returned by an_read or an_preferred

query

character: vector of place name terms to search for. Returned place names will be those that match all entries in query

feature_ids

numeric: return only place names associated with the features identified by these identifiers. Currently these values can only be scar_common_id values

extent

vector of c(longitude_min, longitude_max, latitude_min, latitude_max): if provided, search only for names within this bounding box. extent can also be passed as a raster Extent object, a Raster object (in which case its extent will be used), a Spatial object (in which case the bounding box of the object will be used as the extent), or a matrix (in which case it will be assumed to be the output of sp::bbox)

feature_type

string: return only place names corresponding to feature types matching this pattern. For valid feature type names see an_feature_types

origin

string: return only place names originating from bodies (countries or organisations) matching this pattern. For valid origin values see link{an_origins}

origin_gazetteer

string: return only place names originating from gazetteers matching this pattern. For valid gazetteer names see an_gazetteers

ignore_case

logical: if TRUE, use case-insensitive text matching

as_regex

logical: if TRUE, treat query and other string input parameters as regular expressions. If FALSE, they will be treated as fixed strings to match against

Value

data.frame of results

References

https://data.aad.gov.au/aadc/gaz/scar/, https://www.scar.org/data-products/place-names/

See also

an_read, an_gazetteers, an_origins

Examples

if (FALSE) { # \dontrun{
 g <- an_read(cache = "session")

 ## simple search for any place name containing the word 'William'
 an_filter(g, query = "William")

 ## which bodies (countries or organisations) provided the names in our data?
 an_origins(g)

 ## find names containing "William" and originating from Australia or the USA
 an_filter(g, query = "William", origin = "Australia|United States of America")

 ## this search will return no matches
 ## because the actual place name is 'William Scoresby Archipelago'
 an_filter(g, query = "William Archipelago")

 ## we can split the search terms so that each is matched separately
 an_filter(g, query = c("William", "Archipelago"))

 ## or use a regular expression
 an_filter(g, query = "William .* Archipelago")

 ## or refine the search using feature type
 an_filter(g, query = "William", feature_type = "Archipelago")

 ## what feature types do we have in our data?
 an_feature_types(g)

 ## for more complex text searching, use regular expressions
 ## e.g. names matching "West" or "East"
 an_filter(g, query = "West|East")

 ## names starting with "West" or "East"
 an_filter(g, query = "^(West|East)")

 ## names with "West" or "East" appearing as complete words in the name
 ## ["\b" matches a word boundary: see help("regex") ]
 an_filter(g, query = "\\b(West|East)\\b")

 ## filtering by spatial extent
 nms <- an_filter(g, extent = c(100, 120, -70, -65), origin = "Australia")
 with(nms, plot(longitude, latitude))
 with(nms, text(longitude, latitude, place_name))

 ## searching within the extent of an sp object
 my_sp <- sp::SpatialPoints(cbind(c(100, 120), c(-70, -65)))
 an_filter(g, extent = my_sp)

 ## or equivalently
 an_filter(g, extent = bbox(my_sp))

 ## or using the sp form of the gazetteer data
 gsp <- an_read(cache = "session", sp = TRUE)
 an_filter(gsp, extent = my_sp)

 ## using the pipe operator
 g %>% an_filter(query = "Ross", feature_type = "Ice shelf|Mountain")

 g %>% an_near(loc = c(100, -66), max_distance = 20) %>%
       an_filter(feature_type = "Island")

 ## find all names for feature 1589 and the naming
 ##  authority for each name
 an_filter(g, feature_ids = 1589)[, c("place_name", "origin")]
} # }