spacetime (version 1.3-2)

EOF: Compute spatial or temporal empirical orthogonal function (EOF)

Description

Compute spatial or temporal empirical orthogonal function (EOF)

Usage

eof(x, how = c("spatial", "temporal"), returnEOFs = TRUE, ...)
EOF(x, how = c("spatial", "temporal"), returnPredictions = TRUE, ...)

Value

In spatial mode, the appropriate Spatial* object. In temporal mode, an object of class xts.

Arguments

x

object of class STFDF

how

character; choose "spatial" or "temporal" mode

returnEOFs

logical; if TRUE, the eigenvectors (EOFs) are returned in the form of a Spatial or xts object; if FALSE, the object returned by prcomp is returned, which can be printed, or from which a summary can be computed; see examples.

returnPredictions

logical; if TRUE, the functions are returned (i.e., predicted principle components, or PC scores); if FALSE, the object returned by prcomp is returned, which can be printed, or from which a summary can be computed; see examples (deprecated, see below).

...

arguments passed on to function prcomp; note that scale.=TRUE needs to be specified to obtain EOFs based on correlation (default: covariance)

Examples

if (require(gstat)) {
data(wind)
library(sp)
wind.loc$y = as.numeric(char2dms(as.character(wind.loc[["Latitude"]])))
wind.loc$x = as.numeric(char2dms(as.character(wind.loc[["Longitude"]])))
coordinates(wind.loc) = ~x+y
proj4string(wind.loc) = "+proj=longlat +datum=WGS84"

# match station order to names in wide table:
stations = 4:15
wind.loc = wind.loc[match(names(wind[stations]), wind.loc$Code),]
row.names(wind.loc) = wind.loc$Station
wind$time = ISOdate(wind$year+1900, wind$month, wind$day, 0)
space = list(values = names(wind)[stations])
wind.st = stConstruct(wind[stations], space, wind$time, SpatialObj = wind.loc)
# select firt 500 time steps, to limit run time:
wind.st = wind.st[,1:500]
wind.eof.1 = eof(wind.st)
wind.eof.2 = eof(wind.st, "temporal")
wind.eof.1.PCs = eof(wind.st, returnEOFs = FALSE)
eof(wind.st, "temporal", returnEOFs = FALSE)
summary(eof(wind.st, returnEOFs = FALSE))
summary(eof(wind.st, "temporal", returnEOFs = FALSE))
plot(eof(wind.st, "temporal", returnEOFs = FALSE))
}