daily_df | R Documentation |
Returns a list with data on weather and stations for a selected county.
This function serves as a wrapper to several functions from the rnoaa
package, which pull weather data from all relevant stations in a county.
This function filters and averages data returned by rnoaa
functions
across all weather stations in a county based on user-specified
coverage specifications. For a few of the most common weather variables, we
convert from the original units to more commonly-used units. For example, in
NOAA's data, the temperature values (tmin
, tmax
, and tavg
)
are recorded in tenths of degrees Celsius. This code converts those to degrees
Celsius. Similarly, in NOAA's data the precipitation (prcp
) is recorded
in tenths of millimeters, which this code converts to millimeters. All other
units are left as in NOAA's original data. See NOAA's README file for the
GHCND data (https://www1.ncdc.noaa.gov/pub/data/ghcn/daily/readme.txt) for
more information on the source data that are being pulled.
daily_df( stations, coverage = NULL, var = "all", date_min = NULL, date_max = NULL, average_data = TRUE )
stations |
A dataframe containing station metadata, returned from
the function |
coverage |
A numeric value in the range of 0 to 1 that specifies
the desired percentage coverage for the weather variable (i.e., what
percent of each weather variable must be non-missing to include data from
a monitor when calculating daily values averaged across monitors. The
default is to include all monitors with any available data (i.e.,
|
var |
A character vector specifying desired weather variables. For
example, |
date_min |
A string with the desired starting date in character, ISO format ("yyyy-mm-dd"). The dataframe returned will include only stations that have data for dates including and after the specified date. In other words, if you specify that this equals "1981-02-16", then it will return only the stations with at least some data recorded after Feb. 16, 1981. If a station stopped recording data before Feb. 16, 1981, it will be removed from the set of stations. If not specified, the function will include available stations, regardless of the date when the station started recording data. |
date_max |
A string with the desired ending date in character, ISO format ("yyyy-mm-dd"). The dataframe returned will include only stations that have data for dates up to and including the specified date. If not specified, the function will include available stations, regardless of the date when the station stopped recording data. |
average_data |
TRUE / FALSE to indicate if you want the function to average daily weather data across multiple monitors. If you choose FALSE, the function will return a dataframe with separate entries for each monitor, while TRUE (the default) outputs a single estimate for each day in the dataset, giving the average value of the weather metric across all available monitors in the county that day. |
A list with two elements. daily_data
is a dataframe of daily
weather data averaged across multiple monitors and includes columns
("var"_reporting
) for each weather variable showing the number of
stations contributing to the average for that variable on that day.
The element station_df
is a dataframe of station metadata for each
station contributing weather data. A weather station will have one row per
weather variable to which it contributes data. In addition to information
such as station id, name, latitude, and longitude, the station_df
dataframe includes statistical information about weather values
contributed by each station for each weather variable. These statistics
include calc_coverage
(the percent of non-missing values for each
station-weather variable combination for the specified date range),
standard_dev
(standard deviation), max
, and min
,
(giving the minimum and maximum values), and range
, giving the
range of values in each station-weather variable combination. The
element radius
is the calculated radius within which stations were
pulled from the county's center. Elements lat_center
and
lon_center
are the latitude and longitude of the county's center.
Because this function uses the NOAA API to identify the weather
monitors within a U.S. county, you will need to get an access token from
NOAA to use this function. Visit NOAA's token request page
(http://www.ncdc.noaa.gov/cdo-web/token) to request a token by
email. You then need to set that API code in your R session (e.g., using
options(noaakey = "your key")
, replacing "your key" with the API
key you've requested from NOAA). See the package vignette for more details.
For some weather observations pulled using this function, missing values are coded as a series of "9"s, in some cases starting with a negative symbol. The function underlying this one will automatically convert any value of -9999 to a missing value for the variables "prcp", "tmax", "tmin", "tavg", "snow", and "snwd". However, for some weather observations, there still may be missing values coded using a series of "9"s of some length. You will want to check your final data to see if there are lurking missing values given with series of "9"s.
## Not run: stations <- daily_stations(fips = "12086", date_min = "2010-01-01", date_max = "2010-02-01") fips_list <- countyweather:::daily_df(stations = stations, coverage = 0.90, var = c("tmax", "tmin", "prcp"), date_min = "2010-01-01", date_max = "2010-02-01") averaged_data <- fips_list$daily_data head(averaged_data) station_info <- fips_list$station_df head(station_info) ## End(Not run)
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