occurrences: Get occurrence data

In fozy81/NBN4R: National Biodiversity Network Atlas (UK and Ireland) Data and Resources in R

Description

Retrieve NBN occurrence data via the "occurrence download" web service. At least one of taxon, wkt, or fq must be supplied for a valid query. Note that there is a limit of 500000 records per request when using method="indexed". Use the method="offline" for larger requests. For small requests, method="indexed" likely to be faster.

Usage

occurrences(taxon, wkt, fq, fields, extra, qa, method = "indexed", email,
  download_reason_id = nbn_config()$download_reason_id, reason,
  verbose = nbn_config()$verbose, record_count_only = FALSE,
  use_layer_names = TRUE, use_data_table = TRUE)

Arguments

taxon	string: (optional) query of the form field:value (e.g. "genus:Macropus") or a free text search (e.g. "macropodidae"). Note that a free-text search is equivalent to specifying the "text" field (i.e. taxon="Alaba" is equivalent to taxon="text:Alaba". The text field is populated with the taxon name along with a handful of other commonly-used fields, and so just specifying your target taxon (e.g. taxon="Alaba vibex") will probably work. However, for reliable results it is recommended to use a specific field where possible (see nbn_fields("occurrence_indexed") for valid fields). It is also good practice to quote the taxon name if it contains multiple words, for example taxon="taxon_name:\"Alaba vibex\""
wkt	string: (optional) a WKT (well-known text) string providing a spatial polygon within which to search, e.g. "POLYGON((140 -37,151 -37,151 -26,140.131 -26,140 -37))"
fq	string: (optional) character string or vector of strings, specifying filters to be applied to the original query. These are of the form "INDEXEDFIELD:VALUE" e.g. "kingdom:Fungi". See nbn_fields("occurrence_indexed",as_is=TRUE) for all the fields that are queryable. NOTE that fq matches are case-sensitive, but sometimes the entries in the fields are not consistent in terms of case (e.g. kingdom names "Fungi" and "Plantae" but "ANIMALIA"). fq matches are ANDed by default (e.g. c("field1:abc","field2:def") will match records that have field1 value "abc" and field2 value "def"). To obtain OR behaviour, use the form c("field1:abc OR field2:def"). See e.g. http://wiki.apache.org/solr/CommonQueryParameters for more information about filter queries
fields	string vector: (optional) a vector of field names to return. Note that the columns of the returned data frame are not guaranteed to retain the ordering of the field names given here. If not specified, a default list of fields will be returned. See nbn_fields("occurrence_stored") for valid field names with method indexed, and nbn_fields("occurrence") for valid field names with method offline. Field names can be passed as full names (e.g. "Radiation - lowest period (Bio22)") rather than id ("el871"). Use fields="all" to include all available fields, but note that "all" will probably cause an error with method="offline" because the request URL will exceed the maximum allowable length
extra	string vector: (optional) a vector of field names to include in addition to those specified in fields. This is useful if you would like the default list of fields (i.e. when fields parameter is not specified) plus some additional extras. See nbn_fields("occurrence_stored",as_is=TRUE) for valid field names. Field names can be passed as full names (e.g. "Radiation - lowest period (Bio22)") rather than id ("el871"). Use extra="all" to include all available fields, but note that "all" will probably cause an error with method="offline" because the request URL will exceed the maximum allowable length
qa	string vector: (optional) list of record issues to include in the download. Use qa="all" to include all available issues, or qa="none" to include none. Otherwise see nbn_fields("assertions",as_is=TRUE) for valid values
method	string: "indexed" (default) or "offline". In "offline" mode, more fields are available and larger datasets can be returned
email	string: the email address of the user performing the download (required for method="offline"
download_reason_id	numeric or string: (required unless record_count_only is TRUE) a reason code for the download, either as a numeric ID (currently 0–11) or a string (see nbn_reasons for a list of valid ID codes and names). The download_reason_id can be passed directly to this function, or alternatively set using nbn_config(download_reason_id=...)
reason	string: (optional) user-supplied description of the reason for the download. Providing this information is optional but will help the NBN to better support users by building a better understanding of user communities and their data requests
verbose	logical: show additional progress information? [default is set by nbn_config()]
record_count_only	logical: if TRUE, return just the count of records that would be downloaded, but don't download them. Note that the record count is always re-retrieved from the NBN, regardless of the caching settings. If a cached copy of this query exists on the local machine, the actual data set size may therefore differ from this record count. record_count_only=TRUE can only be used with method="indexed"
use_layer_names	logical: if TRUE, layer names will be used as layer column names in the returned data frame (e.g. "watsonianViceCounties"). Otherwise, layer id value will be used for layer column names (e.g. "cl23")
use_data_table	logical: if TRUE, attempt to read the data.csv file using the fread function from the data.table package. Requires data.table to be available. If this fails with an error or warning, or if use_data_table is FALSE, then read.table will be used (which may be slower)

Value

Data frame of occurrence results, with one row per occurrence record. The columns of the dataframe will depend on the requested fields

References

• Associated NBN web service for record counts: https://api.nbnatlas.org/#ws3

• Associated NBN web service for occurence downloads: https://api.nbnatlas.org/#ws4

• Field definitions: https://docs.google.com/spreadsheet/ccc?key=0AjNtzhUIIHeNdHhtcFVSM09qZ3c3N3ItUnBBc09TbHc

• WKT reference: http://www.geoapi.org/3.0/javadoc/org/opengis/referencing/doc-files/WKT.html

See Also

nbn_reasons for download reasons; nbn_config

Examples

## Not run: 
## count of records from this data provider
x <- occurrences(taxon="data_resource_uid:dr356",record_count_only=TRUE)
## download records, with standard fields
x <- occurrences(taxon="data_resource_uid:dr356",download_reason_id=10)
## download records, with all fields
x <- occurrences(taxon="data_resource_uid:dr356",download_reason_id=10,
  fields=nbn_fields("occurrence_stored",as_is=TRUE)$name) 
## download records, with specified fields
x <- occurrences(taxon="genus:macropus",fields=c("longitude","latitude",
  "common_name","taxon_name","Rights"),download_reason_id=10)
 ## download records in polygon, with no quality assertion information
x <- occurrences(taxon="genus:Sialis",wkt="POLYGON((-3 56,-4 56,-4 57,-3 57,-3 56))", 
download_reason_id=10,qa="none",verbose = T)

y <- occurrences(taxon="taxon_name:\"Sialis lutaria\"",fields=c("latitude","longitude","collector"),
download_reason_id=10)
str(y)
# equivalent direct webservice call [see this by setting nbn_config(verbose=TRUE)]:
# https://records-ws.nbnatlas.org/occurrences/index/download?q=taxon_name%
# 3A%22Sialis%20lutaria%22&fields=latitude%2Clongitude%2Cbasis_of_record&
# reasonTypeId=10&sourceTypeId=2001&esc=%5C&sep=%09&file=data

occurrences(taxon="genus:\"Sialis\"",fields=c("latitude","longitude","collector"),
  qa="none",fq="collector:Unknown",download_reason_id=10)
# equivalent direct webservice call [see this by setting nbn_config(verbose=TRUE)]:
# https://records-ws.nbnatlas.org/occurrences/index/download?reasonTypeId=10&q=*:*&
# fq=genus:Vulpes&lat=51.5074&lon=0.1278&radius=10.0&qa=none&fields=latitude,longitude&
# reasonTypeId=10&sourceTypeId=2001 

## End(Not run)

fozy81/NBN4R documentation built on May 19, 2019, 8:22 a.m.