search_safe: SAFE dataset search functions.

Description Usage Arguments Details Value Functions Spatial searches Links Examples

Description

In addition to the datasets stored on Zenodo, the SAFE Project website provides an API to search dataset metadata in more depth. The search functions access this API and return safe_record_set objects identifying datasets that match a particular query.

Usage

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search_dates(dates, match_type = "intersect", most_recent = FALSE, ids = NULL)

search_fields(
  field_text = NULL,
  field_type = NULL,
  ids = NULL,
  most_recent = FALSE
)

search_authors(author, ids = NULL, most_recent = FALSE)

search_taxa(
  taxon_name = NULL,
  taxon_rank = NULL,
  gbif_id = NULL,
  ids = NULL,
  most_recent = FALSE
)

search_text(text, ids = NULL, most_recent = FALSE)

search_spatial(
  wkt = NULL,
  location = NULL,
  distance = NULL,
  ids = NULL,
  most_recent = FALSE
)

Arguments

dates

A vector of length 1 or 2, containing either ISO format date character strings ('yyyy-mm-dd') or POSIXt dates.

match_type

A character string (see Details).

most_recent

Logical indicating whether to restrict the API to returning only the most recent versions of the datasets found. By default all versions of matching dataset concepts are returned.

ids

A set of SAFE dataset record IDs to restrict a search. This will typically be a safe_record_set object returned by another search but can also be a vector of record ids in any of the formats accepted by validate_record_ids.

field_text

Text to search for within the data worksheet field name and description.

field_type

A data worksheet field type (see Links).

author

A character string used to search for datasets by author full (or partial) names.

taxon_name

The scientific name of a taxon to search for.

taxon_rank

A taxonomic rank to search for.

gbif_id

A GBIF taxonomic ID number.

text

Character string to look for within a SAFE dataset, worksheet, title, field description, and dataset keywords.

wkt

A well-known text geometry string, assumed to use latitude and longitude in WGS84 (EPSG:4326).

location

The name of a location in the SAFE gazetteer.

distance

A buffer distance for spatial searches, giving the distance in metres within which to match either location or wkt searches.

Details

The API provides endpoints to search datasets by date extents, data worksheet fields, authors, taxa, free text and by spatial query. All of the functions accept the argument most_recent, which restricts the returned datasets to the most recent versions of each matching dataset concept. The functions can also be passed an existing safe_record_set object to search within the results of a previous search.

The match_type parameter specifies how to match date ranges and must be one of 'intersect' (default), 'contain', or 'within'. The 'contain' option returns datasets that span a date range, 'within' returns datasets that fall within the given range and 'intersect' selects datasets that overlap any part of the date range. Note that match_type is ignored when only a single date is provided.

Value

An object of class safe_record_set of datasets that match the query.

Functions

Spatial searches

For spatial searches, users can select a location name from a SAFE data gazetteer (see e.g. https://www.safeproject.net/info/gazetteer or load_gazetteer) or provide a WKT geometry. The sampling locations provided in each SAFE dataset are tested to see if they intersect the search geometry.

A buffer distance can aso be provided to extend the search around the query geometry. Note that although WKT geometries should be provided using WGS84 lat/long coordinates, since this is typical field GPS data, distances must be provided as metres and all proximity calculations take place in the UTM50N projected coordinate system.

The search_spatial function will not retrieve datasets that have not provided sampling locations or use newly defined locations that are missing coordinate information.

Links

SAFE data API

e.g. https://www.safeproject.net/api

Worksheet field types

https://safedata-validator.readthedocs.io/en/latest/data_format/data/#field-types

SAFE gazetteer

See load_gazetteer and e.g. https://www.safeproject.net/info/gazetteer

WKT

https://en.wikipedia.org/wiki/Well-known_text_representation_of_geometry

Examples

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   ## Not run: 
   search_dates('2014-06-12')
   search_dates(as.POSIXct(c('2014-06-12', '2015-06-11')))
   search_dates(c('2014-06-12', '2015-06-11'), match_type = 'contain')
   search_fields(field_text = 'temperature')
   search_fields(field_type = 'numeric')
   search_fields(field_text = 'temperature', field_type = 'numeric')
   search_authors('Ewers')
   search_taxa(taxon_name = 'Formicidae')
   search_taxa(gbif_id = 4342)
   search_taxa(taxon_rank = 'family')
   search_text('forest')
   search_text('ant')
   search_spatial(wkt = 'Point(116.5 4.75)')
   search_spatial(wkt = 'Point(116.5 4.75)', distance = 100000)
   search_spatial(wkt = 'Polygon((110 0, 110 10,120 10,120 0,110 0))')
   search_spatial(location = 'A_1')
   search_spatial(location = 'A_1', distance = 2500)
   
## End(Not run)

ImperialCollegeLondon/safe_data documentation built on Jan. 29, 2020, 10:19 p.m.