corRExpwr2Dt | R Documentation |
This function is a constructor for the 'corRExpwr2Dt'
class, representing a non-separable spatial correlation structure for temporally integrated measurements. Letting rs
denote the spatial range, ps
the spatial shape, rt
the temporal range, and lambda
the space-time interaction, the correlation between two observations a distance d
apart in space and t
in time is \exp(-(d/rs)^ps - t/rt - \lambda (d/rs)^ps (t/rt))
.
corRExpwr2Dt(value = numeric(0), form = ~ 1,
metric = c("euclidean", "maximum", "manhattan", "haversine"),
radius = 3956)
value |
optional numeric vector of four parameter values for the powered exponential correlation structure, corresponding to the “spatial range”, “spatial shape”, “temporal range”, and “space-time interaction”. The range parameter values must be greater than zero, the shape in the interval (0, 2], and the interaction greater than or equal to zero. Defaults to |
form |
one-sided formula of the form |
metric |
optional character string specifying the distance metric to be used. The currently available options are |
radius |
radius to be used in the haversine formula for great-circle distance. Defaults to the Earth's radius of 3,956 miles. |
Object of class 'corRExpwr2Dt'
, also inheriting from class 'corRSpatial'
, representing a non-separable spatial correlation structure.
When "haversine"
is used as the distance metric, longitude and latitude coordinates must be given as the first and second covariates, respectively, in the formula specification for the form
argument.
Brian Smith brian-j-smith@uiowa.edu
Cressie, N. and Huang, H.-C. (1993) “Classes of Nonseperable, Spatio-Temporal Stationary Covariance Functions”, Journal of the American Statistical Association, 94, 1330-1340.
Smith, B.J. and Oleson, J.J. (2007) “Geostatistical Hierarchical Model for Temporally Integrated Radon Measurements”, Jounal of Agricultural, Biological, and Environmental Statistics, in press.
corRClasses
sp1 <- corRExpwr2Dt(form = ~ x + y + t1 + t2)
spatDat <- data.frame(x = (0:4)/4, y = (0:4)/4, t1=(0:4)/4, t2=(1:5)/4)
cs1ExpwrDt <- corRExpwr2Dt(c(1, 1, 1, 1), form = ~ x + y + t1 + t2)
cs1ExpwrDt <- Initialize(cs1ExpwrDt, spatDat)
corMatrix(cs1ExpwrDt)
cs2ExpwrDt <- corRExpwr2Dt(c(1, 1, 1, 1), form = ~ x + y + t1 + t2, metric = "man")
cs2ExpwrDt <- Initialize(cs2ExpwrDt, spatDat)
corMatrix(cs2ExpwrDt)
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