stxplore (version 0.1.0)

emp_orth_fun: Computes empirical orthogonal functions using a dataframe or a stars object.

Description

Computes empirical orthogonal functions of the data. Function autoplot can plot the output.

Usage

emp_orth_fun(x, ...)
# S3 method for data.frame
emp_orth_fun(x, values_df, ...)
# S3 method for stars
emp_orth_fun(x, ...)
# S3 method for emporthfun
autoplot(
  object,
  EOF_num = 1,
  palette = "Spectral",
  only_EOF = FALSE,
  only_TS = FALSE,
  ...
)

Value

An emporthfun object with temporal PCs and spatial EOFs.

Arguments

x

The dataframe or stars object. If it is a dataframe, then it should have the locations.

...

Other arguments currently ignored.

values_df

For dataframes: the dataframe of dimension length(times) x length(locations) containing the quantity of interest.

object

For autoplot: the output of the function `emp_orth_fun'.

EOF_num

For autoplot: the number of Empirical Orthogonal Functions (EOFs) to plot.

palette

The color palette. Default is Spectral.

only_EOF

For autoplot: if TRUE, only the spatial EOF function would be plotted.

only_TS

For autoplot: if TRUE, only the PC time series would be plotted. If both are set to FALSE, both plots would be displayed. Both cannot be set to TRUE.

Examples

# dataframe example
data(SSTlonlatshort)
data(SSTdatashort)
data(SSTlandmaskshort)
delete_rows <- which(SSTlandmaskshort  ==  1)
SSTdatashort   <- SSTdatashort[-delete_rows, 1:396]
emp1 <- emp_orth_fun(SSTlonlatshort[-delete_rows,  ],
                     SSTdatashort)
autoplot(emp1,
         EOF_num = 1)


# stars example
library(dplyr)
library(stars)
# Create a stars object from a data frame
precip_df <- NOAA_df_1990[NOAA_df_1990$proc == 'Precip', ] %>%
  filter(date >= "1992-02-01" & date <= "1992-02-05")
precip <- precip_df[ ,c('lat', 'lon', 'date', 'z')]
st_precip <- st_as_stars(precip, dims = c("lon", "lat", "date"))
emp <- emp_orth_fun(st_precip)
autoplot(emp, only_TS = TRUE)