NCEP.array2df {RNCEP} | R Documentation |
Convert data from an array to a data frame
Description
This function takes a 3-dimensional array of weather data, as returned by NCEP.gather
, and converts it to a dataframe composed of latitude, longitude, datetime, and the weather data.
Usage
NCEP.array2df(wx.data, var.names=NULL)
Arguments
wx.data |
either a single 3-D array of weather data, as returned by |
var.names |
an optional vector of names for the weather variables in the 3-D arrays to be used in the output data frame |
Details
This is a function to convert the data contained in one or many arrays to a single data.frame.
The order of the names specified in var.names
should correspond to the order of the list of input arrays in wx.data
. Latitude, longitude, and datetime are named automatically and cannot be changed in the function call.
When converting the data from two or more 3-D arrays to a single data frame, all 3-D arrays must contain the exact same spatial and temporal dimensions and intervals.
Value
A data frame with the components of latitudes, longitude, datetime, and the weather variable(s) from the input data array(s).
Author(s)
Michael U. Kemp mukemp+RNCEP@gmail.com
References
Kemp, M. U., van Loon, E. E., Shamoun-Baranes, J., and Bouten, W. 2011. RNCEP:global weather and climate data at your fingertips. – Methods in Ecology and Evolution. DOI:10.1111/j.2041-210X.2011.00138.x.
Examples
## Not run:
library(RNCEP)
############################################################
############################################################
## In this first example, we take data from a single 3-D array
## and arrange them in a data.frame ##
#############################################################
## First query the temperature for a particular pressure level
## and datetime range ##
wx.extent <- NCEP.gather(variable='air', level=850,
months.minmax=c(8,9), years.minmax=c(2006,2007),
lat.southnorth=c(50,55), lon.westeast=c(0,5),
reanalysis2 = FALSE, return.units = TRUE)
## Then convert the 3-D array to a data.frame ##
wx.df <- NCEP.array2df(wx.data=wx.extent, var.names='Temperature')
############################################################
############################################################
## In this second example, we take data from two 3-D arrays
## and arrange them in a single data.frame ##
#############################################################
## Query the U (east/west) and V (north/south) wind components
## for a particular pressure level and datetime range ##
wx.uwnd <- NCEP.gather(variable='uwnd', level=850,
months.minmax=c(8,9), years.minmax=c(2006,2007),
lat.southnorth=c(50,55), lon.westeast=c(0,5),
reanalysis2 = FALSE, return.units = TRUE)
wx.vwnd <- NCEP.gather(variable='vwnd', level=850,
months.minmax=c(8,9), years.minmax=c(2006,2007),
lat.southnorth=c(50,55), lon.westeast=c(0,5),
reanalysis2 = FALSE, return.units = TRUE)
## Then convert the two 3-D arrays to a single data.frame ##
wx.df <- NCEP.array2df(wx.data=list(wx.uwnd, wx.vwnd),
var.names=c('Uwind', 'Vwind'))
## End(Not run)