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

In stxplore: Exploration of Spatio-Temporal Data

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 class 'data.frame'
emp_orth_fun(x, values_df, ...)

## S3 method for class 'stars'
emp_orth_fun(x, ...)

## S3 method for class 'emporthfun'
autoplot(
  object,
  EOF_num = 1,
  palette = "Spectral",
  only_EOF = FALSE,
  only_TS = FALSE,
  ...
)

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.

Value

An emporthfun object with temporal PCs and spatial EOFs.

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)

stxplore documentation built on Feb. 16, 2023, 9:53 p.m.