R/observation.error.R

In verification: Weather Forecast Verification Utilities

# *=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=* 
# ** Copyright UCAR (c) 1992 - 2004 
# ** University Corporation for Atmospheric Research(UCAR) 
# ** National Center for Atmospheric Research(NCAR) 
# ** Research Applications Program(RAP) 
# ** P.O.Box 3000, Boulder, Colorado, 80307-3000, USA 
# ** 2004/9/1 14:13:55 
# *=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=* 
observation.error <- function(obs, gold.standard = NULL, ...){

if(is.null(gold.standard) & length(obs) ==4 ){
## assume data entered as c(n11, n10, n01, n00)
n11<- obs[1]
n10<- obs[2]
n01<- obs[3]
n00<- obs[4]
  return( list( t = n11/(n11+n01), u = n10/(n10+n00) ))
} else {
A   <- table(data.frame( obs, gold.standard) )
n11 <- A[2,2]
n00 <- A[1,1]
n10 <- A[2,1]
n01 <- A[1,2]

return( list(t = n11/(n11+n01), u = n10/(n10+n00) ) )
}

}