opensensmapR/man/osem_measurements.Rd

% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/measurement.R
\name{osem_measurements}
\alias{osem_measurements}
\alias{osem_measurements.default}
\alias{osem_measurements.bbox}
\alias{osem_measurements.sensebox}
\title{Fetch the Measurements of a Phenomenon on opensensemap.org}
\usage{
osem_measurements(x, ...)

\method{osem_measurements}{default}(x, ...)

\method{osem_measurements}{bbox}(x, phenomenon, exposure = NA,
  from = NA, to = NA, columns = NA, ...,
  endpoint = osem_endpoint(), progress = T, cache = NA)

\method{osem_measurements}{sensebox}(x, phenomenon, exposure = NA,
  from = NA, to = NA, columns = NA, ...,
  endpoint = osem_endpoint(), progress = T, cache = NA)
}
\arguments{
\item{x}{Depending on the method, either
\enumerate{
  \item a \code{chr} specifying the phenomenon, see \code{phenomenon}
  \item a \code{\link[sf]{st_bbox}} to select sensors spatially,
  \item a \code{sensebox data.frame} to select boxes from which
    measurements will be retrieved,
}}

\item{...}{see parameters below}

\item{phenomenon}{The phenomenon to retrieve measurements for}

\item{exposure}{Filter sensors by their exposure ('indoor', 'outdoor', 'mobile')}

\item{from}{A \code{POSIXt} like object to select a time interval}

\item{to}{A \code{POSIXt} like object to select a time interval}

\item{columns}{Select specific column in the output (see openSenseMap API documentation)}

\item{endpoint}{The URL of the openSenseMap API}

\item{progress}{Whether to print download progress information}

\item{cache}{Whether to cache the result, defaults to false.
If a valid path to a directory is given, the response will be cached there. Subsequent identical requests will return the cached data instead.}
}
\value{
An \code{osem_measurements data.frame} containing the
  requested measurements
}
\description{
Measurements can be retrieved either for a set of boxes, or through a spatial
bounding box filter. To get all measurements, the \code{default} function applies
a bounding box spanning the whole world.
}
\section{Methods (by class)}{
\itemize{
\item \code{default}: Get measurements from \strong{all} senseBoxes.

\item \code{bbox}: Get measurements by a spatial filter.

\item \code{sensebox}: Get measurements from a set of senseBoxes.
}}

\examples{
\donttest{
  # get measurements from all boxes on the phenomenon 'PM10' from the last 48h
  m = osem_measurements('PM10')

  # get measurements from all mobile boxes on the phenomenon 'PM10' from the last 48h
  m = osem_measurements('PM10', exposure = 'mobile')

  # get measurements and cache them locally in the working directory.
  # subsequent identical requests will load from the cache instead, ensuring
  # reproducibility and saving time and bandwidth!
  m = osem_measurements('PM10', exposure = 'mobile', cache = getwd())
  m = osem_measurements('PM10', exposure = 'mobile', cache = getwd())

  # get measurements returning a custom selection of columns
  m = osem_measurements('PM10', exposure = 'mobile', columns = c(
    'value',
    'boxId',
    'sensorType',
    'lat',
    'lon',
    'height'
  ))
}
\donttest{
  # get measurements from sensors within a custom WGS84 bounding box
  bbox = structure(c(7, 51, 8, 52), class = 'bbox')
  m = osem_measurements(bbox, 'Temperatur')

  # construct a bounding box 12km around berlin using the sf package,
  # and get measurements from stations within that box
  library(sf)
  bbox2 = st_point(c(13.4034, 52.5120)) \%>\%
    st_sfc(crs = 4326) \%>\%
    st_transform(3857) \%>\% # allow setting a buffer in meters
    st_buffer(set_units(12, km)) \%>\%
    st_transform(4326) \%>\% # the opensensemap expects WGS 84
    st_bbox()
  m = osem_measurements(bbox2, 'Temperatur', exposure = 'outdoor')

  # construct a bounding box from two points,
  # and get measurements from stations within that box
  points = st_multipoint(matrix(c(7.5, 7.8, 51.7, 52), 2, 2))
  bbox3 = st_bbox(points)
  m = osem_measurements(bbox2, 'Temperatur', exposure = 'outdoor')
}
\donttest{
  # get measurements from a set of boxes
  b = osem_boxes(grouptag = 'ifgi')
  m4 = osem_measurements(b, phenomenon = 'Temperatur')

  # ...or a single box
  b = osem_box('57000b8745fd40c8196ad04c')
  m5 = osem_measurements(b, phenomenon = 'Temperatur')

  # get measurements from a single box on the from the last 40 days.
  # requests are paged for long time frames, so the APIs limitation
  # does not apply!
  library(lubridate)
  m1 = osem_measurements(
    b,
    'Temperatur',
    to = now(),
    from = now() - days(40)
  )
}
}
\seealso{
\href{https://docs.opensensemap.org/#api-Measurements-getDataMulti}{openSenseMap API documentation (web)}

\code{\link{osem_box}}

\code{\link{osem_boxes}}

\code{\link{osem_clear_cache}}
}