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This function is primarily used to find a site code that can be used to access data using import_isd_hourly(). Sites searches of approximately 30,000 sites can be carried out based on the site name and based on the nearest locations based on user-supplied latitude and longitude.

Usage

import_isd_stations(
  site = NULL,
  lat = NULL,
  lon = NULL,
  crs = 4326,
  country = NULL,
  state = NULL,
  n_max = 10,
  end_year = "current",
  provider = c("OpenStreetMap", "Esri.WorldImagery"),
  return = c("table", "sf", "map")
)

Arguments

site

A site name search string e.g. site = "heathrow". The search strings and be partial and can be upper or lower case e.g. site = "HEATHR".

lat, lon

Decimal latitude and longitude (or other Y/X coordinate if using a different crs). If provided, the n_max closest ISD stations to this coordinate will be returned.

crs

The coordinate reference system (CRS) of the data, passed to sf::st_crs(). By default this is EPSG:4326, the CRS associated with the commonly used latitude and longitude coordinates. Different coordinate systems can be specified using crs (e.g., crs = 27700 for the British National Grid). Note that non-lat/lng coordinate systems will be re-projected to EPSG:4326 for making comparisons with the NOAA metadata plotting on the map.

country

The country code. This is a two letter code. For a full listing see https://www1.ncdc.noaa.gov/pub/data/noaa/isd-history.csv.

state

The state code. This is a two letter code.

n_max

The number of nearest sites to search based on latitude and longitude.

end_year

To help filter sites based on how recent the available data are. end_year can be "current", "any" or a numeric year such as 2016, or a range of years e.g. 1990:2016 (which would select any site that had an end date in that range. By default only sites that have some data for the current year are returned.

provider

By default a map will be created in which readers may toggle between a vector base map and a satellite/aerial image. provider allows users to override this default; see http://leaflet-extras.github.io/leaflet-providers/preview/ for a list of all base maps that can be used. If multiple base maps are provided, they can be toggled between using a "layer control" interface.

return

The type of R object to import the ISD stations as. One of the following:

  • "table", which returns an R data.frame.

  • "sf", which returns a spatial data.frame from the sf package.

  • "map", which returns an interactive leaflet map.

Value

A data frame is returned with all available meta data, mostly importantly including a code that can be supplied to importNOAA(). If latitude and longitude searches are made an approximate distance, dist in km is also returned.

Author

David Carslaw

Examples

if (FALSE) { # \dontrun{
## search for sites with name beijing
getMeta(site = "beijing")
} # }

if (FALSE) { # \dontrun{
## search for near a specified lat/lon - near Beijing airport
## returns 'n_max' nearest by default
getMeta(lat = 40, lon = 116.9)
} # }