getOccurrences: Get occurrences for a given species
In rnbn: Access NBN Data

Description Usage Arguments Value Author(s) See Also Examples

Gets occurrence data from the NBN to which you have access. To get access to data you must first register at https://data.nbn.org.uk/User/Register. You will need your username and password when running this function for the first time.
You can specify the data to retrieve by dataset, species, time, location and/or group.

getOccurrences(tvks = NULL, datasets = NULL, startYear = NULL,
  endYear = NULL, VC = NULL, group = NULL, gridRef = NULL,
  polygon = NULL, point = NULL, radius = 5000, latLong = TRUE,
  acceptTandC = FALSE, silent = FALSE, attributes = FALSE, ...)

`tvks`	a list of TVKs which are strings of 16 alphanumeric characters. You can look these up using `getTVKQuery`
`datasets`	a list of dataset keys which are strings of 8 alphanumeric characters. Look up datasets here: https://data.nbn.org.uk/Datasets
`startYear`	a 4 digit integer year
`endYear`	a 4 digit integer year
`VC`	a string giving a vice-county name (see `listVCs`)
`group`	a string giving the name of a group (see `listGroups`). Using group will retireve data for all TVKs in this group. for example using group 'reptile' will search using over 150 TVKs including TVKs for higher taxonomic groups such families within reptiles. Therefore it may be preferrable to search using a list TVKs aquired using getTVKQuery
`gridRef`	a string giving a gridreference in which to search for occurrences
`polygon`	A WKT (Well-Known Text) polygon string. Note that polygons containing many verticies (>100) are likely to create queries that exceed the NBN character limit
`point`	A vector of two numbers; latitude, longitude. Used with `radius`.
`radius`	A numeric distance, in meters used with `point` to create a circular search area.
`latLong`	logical, if TRUE latitude and longitude are returned as additional columns. The conversion to latitude and longitude is currently accurate to about about ~20 meters, greater than the vast majoring of records' precision.
`acceptTandC`	if set to `TRUE` you accept the NBN gateway terms and conditions and privacy policy. These can be found at https://data.nbn.org.uk/Terms. Accepting the terms and conditions supresses the corresponding warning message.
`silent`	If `TRUE` batch request information is supressed
`attributes`	If `FALSE` then attribute data is not returned, this may improve the speed of large requests.
`...`	Further named parameters passed on to `GET`

a data.frame of occurence records. Details of the data providers that contributed to the data returned is given as a 'providers' attribute

Stuart Ball, JNCC stuart.ball@jncc.gov.uk and Tom August, CEH tomaug@ceh.ac.uk

getFeature, getTVKQuery, listVCs, listDatasets, listGroups

## Not run:  
 dt1 <- getOccurrences(tvks="NBNSYS0000002987", datasets="GA000373", 
                       startYear="1990", endYear="1991")
                      
 dt2 <- getOccurrences(tvks=c("NBNSYS0000002987","NHMSYS0001688296","NHMSYS0000080210"),
                       startYear="1990", endYear="1991")
                       
 dt3 <- getOccurrences(group="quillwort", startYear="1990", endYear="2010",
                       VC="Shetland (Zetland)")
 
 # Get the data providers information
 dp <- attr(dt1,'providers')                      
                       

## End(Not run)