spacetime (version 1.1-5)

STFDF-class: Class "STFDF"

Description

A class for spatio-temporal data with full space-time grid; for n spatial locations and m times, n x m observations are available

Usage

STF(sp, time, endTime = delta(time))
  STFDF(sp, time, data, endTime = delta(time))
  ## S3 method for class 'STFDF':
[(x, i, j, ..., drop = is(x, "STFDF"))
  ## S3 method for class 'STFDF,xts':
coerce(from, to, strict=TRUE)
  ## S3 method for class 'STFDF,Spatial':
coerce(from, to)

Arguments

sp

object of class Spatial, having n elements

time

object holding time information, of length m; see ST for details

endTime

vector of class POSIXct, holding end points of time intervals; by default, time intervals equal the time step width, see delta

data

data frame with n*m rows corresponding to the observations (spatial index moving fastest)

x

an object of class STFDF

i

selection of spatial entities

j

selection of temporal entities (see syntax in package xts)

...

selection of attribute(s)

drop

if TRUE and a single spatial entity is selected, an object of class xts is returned; if TRUE and a single temporal entity is selected, and object of the appropriate Spatial class is returned; if FALSE, no coerc

from

object of class STFDF

to

target class

strict

ignored

Value

• the as.data.frame coercion returns the full long table, with purely spatial attributes and purely time attributes replicated appropriately.

Objects from the Class

Objects of this class represent full space/time data with a full grid (or lattice) layout

References

http://www.jstatsoft.org/v51/i07/

Examples

sp = cbind(x = c(0,0,1), y = c(0,1,1))
row.names(sp) = paste("point", 1:nrow(sp), sep="")
library(sp)
sp = SpatialPoints(sp)
time = as.POSIXct("2010-08-05")+3600*(10:13)
m = c(10,20,30) # means for each of the 3 point locations
mydata = rnorm(length(sp)*length(time),mean=rep(m, 4))
IDs = paste("ID",1:length(mydata))
mydata = data.frame(values = signif(mydata,3), ID=IDs)
stfdf = STFDF(sp, time, mydata)
stfdf
stfdf[1:2,]
stfdf[,1:2]
stfdf[,,2]
stfdf[,,"values"]
stfdf[1,]
stfdf[,2]
as(stfdf[,,1], "xts")
as(stfdf[,,2], "xts")
# examples for [[, [[<-, $ and $<- 
stfdf[[1]]
stfdf[["values"]]
stfdf[["newVal"]] <- rnorm(12)
stfdf$ID
stfdf$ID = paste("OldIDs", 1:12, sep="")
stfdf$NewID = paste("NewIDs", 12:1, sep="")
stfdf
x = stfdf[stfdf[1:2,],] 
all.equal(x, stfdf[1:2,]) 
all.equal(stfdf, stfdf[stfdf,]) # converts character to factor...