Destination Weather API

Weather forecasts, reports on current weather conditions, astronomical information and alerts at a specific location based on the ‘HERE Destination Weather’ API.

Observations

In order to request information about the current weather situation points of interest (POIs) have to be provided. The POIs must be an sf object containing geometries of type POINT or a character vector containing place names (e.g. cities). These POIs are passed to the weather() function, whereby the product parameter is set to "observation":

observation <- weather(
  poi = poi,
  product = "observation"
)

The return value is an sf object, which contains the POINT geometries of the provided POIs and the most recent record on the observed weather. The measurements are taken from the nearest weather observation stations with respect to the POIs. The distance of the stations to the provided POIs is an indicator for the reliabilty of the weather information at each POI. A table of the observed weather near the example POIs:

station distance description temperature humidity windSpeed windDirection
Rönnimoos 450 Low clouds. Quite cool. 7.00 87 0.00 0
Lugano 670 Clear. Cool. 8.00 82 5.56 210
Chailly 340 Low clouds. Quite cool. 7.00 87 3.71 0
Kleinhüningen 430 Mostly cloudy. Chilly. 4.00 93 3.71 0
Kehrsatz 620 Partly sunny. Quite cool. 6.00 100 5.56 0
Zürich (Kreis 6) / Oberstrass 820 Sprinkles. Mostly cloudy. Quite cool. 6.00 93 5.56 40
Geneva 490 Partly sunny. Quite cool. 7.00 87 1.85 0
Vaduz 940 Sprinkles. Cloudy. Quite cool. 5.78 92 1.85 190

Print the weather observation information on an interactive leaflet map:

if (requireNamespace("mapview", quietly = TRUE)) {
  m <-
    mapview::mapview(observation,
                     zcol = "temperature",
                     cex = observation$humidity/4,
                     layer.name = "Observation",
                     map.types = c("Esri.WorldTopoMap"),
                     homebutton = FALSE
    ) +
    mapview::mapview(poi,
                     zcol = "city",
                     cex = 1,
                     col.region = "black",
                     legend = FALSE,
                     homebutton = FALSE
    )
  m
}

Forecast

An hourly forecast of the predicted weather for the following seven days can be obtained by setting the product parameter to "forecast_hourly":

forecast <- weather(
  poi = poi,
  product = "forecast_hourly"
)

Print the weather observation information on an interactive leaflet map with popup graphs for temperature and humidity:

  1. Create a list containing the temperature and humidity graphs for every POI:
if (requireNamespace("ggplot2", quietly = TRUE)) {
  g <- lapply(seq_len(nrow(forecast)), function(x) {
    fc <- data.frame(
      dt = as.POSIXct(forecast$forecast[[x]]$utcTime, format = "%Y-%m-%dT%H:%M:%OS", tz = "UTC"),
      te = as.numeric(forecast$forecast[[x]]$temperature),
      rh = as.numeric(forecast$forecast[[x]]$humidity)
    )
    ggplot2::ggplot(fc, ggplot2::aes(x = dt)) +
      ggplot2::geom_line(ggplot2::aes(y = te, colour = "Temperature")) +
      ggplot2::geom_line(ggplot2::aes(y = rh/5, colour = "Humidity")) +
      ggplot2::scale_y_continuous(sec.axis = ggplot2::sec_axis(~.*5, name = "Relative humidity [%]")) +
      ggplot2::scale_colour_manual(values = c("blue", "red")) +
      ggplot2::labs(y = "Air temperature [°C]", x = "", colour = "") +
      ggplot2::ggtitle(forecast$station[x]) +
      ggplot2::theme_minimal() +
      ggplot2::theme(legend.position="bottom", panel.background = ggplot2::element_rect(color = NA))
  })
}
  1. Then add list of graphs to the leaflet map using the the popup parameter:
if (requireNamespace(c("ggplot2", "mapview", "leafpop"), quietly = TRUE)) {
  m <-
    mapview::mapview(forecast,
                     color = "black",
                     col.region = "yellow",
                     layer.name = "Weather station",
                     zcol = "station",
                     map.types = c("Esri.WorldTopoMap"),
                     homebutton = FALSE,
                     legend = FALSE,
                     popup = leafpop::popupGraph(g)
    ) +
    mapview::mapview(poi,
                     zcol = "city",
                     cex = 1,
                     col.region = "black",
                     layer.name = "POI",
                     legend = FALSE,
                     homebutton = FALSE
    )
  m
}

Astronomy

An astronomical forecast is requested by setting the product parameter to "forecast_astronomy":

astronomy <- weather(
  poi = poi,
  product = "forecast_astronomy"
)

Print a table for the sun and moon times of the first example POI, where the nearest station is ‘Emmenbrücke’:

date sunrise sunset moonrise moonset phase
2021-01-31 7:54AM 5:27PM 8:40PM 9:41AM Waning gibbous
2021-02-01 7:52AM 5:29PM 9:57PM 10:04AM Waning gibbous
2021-02-02 7:51AM 5:30PM 11:14PM 10:26AM Waning gibbous
2021-02-03 7:50AM 5:32PM
10:49AM Waning gibbous
2021-02-04 7:48AM 5:33PM 12:31AM 11:13AM Last Quarter
2021-02-05 7:47AM 5:35PM 1:50AM 11:41AM Last Quarter
2021-02-06 7:46AM 5:36PM 3:08AM 12:15PM Waning crescent
2021-02-07 7:44AM 5:38PM 4:23AM 12:58PM Waning crescent

Alerts

Current weather alerts, near provided POIs, are obtain by the product alerts:

alerts <- weather(
  poi = poi,
  product = "alerts"
)

This returns an sf object with the POIs and the attribute "alerts", which is a data.table, which contains the current weather alerts. If no alerts are recorded near a POI the attribute "alerts" is NULL.

API Reference