rtop (version 0.5-14)

rtopFitVariogram: Fit variogram model to sample variogram of data with spatial support

Description

rtopFitVariogram will fit a variogram model to the estimated binned variogram or cloud variogram of data with an areal support.

Usage

# S3 method for rtop
rtopFitVariogram(object, params = list(), ...) 
# S3 method for SpatialPolygonsDataFrame
rtopFitVariogram(object, params=list(), ...) 
# S3 method for SpatialPointsDataFrame
rtopFitVariogram(object, params=list(), ...) 
# S3 method for rtopVariogram
rtopFitVariogram(object, observations, dists = NULL, 
                    params=list(), mr = FALSE, aOver = NULL, ...) 
# S3 method for rtopVariogramCloud
rtopFitVariogram(object, observations, dists = NULL, 
                    aOver = NULL, params=list(), mr = FALSE, ...)

Value

The function creates an object with the fitted variogram Model (variogramModel) and a

data.frame (varFit) with the differences between the sample semivariances and the regularized semivariances. If mr = TRUE, the function also returns other objects (discretized elements and geostatistical distances, if created) as a part of the returned object. If the function is called with an rtop-object as argument, it will return an rtop-object with variogramModel and varFit added to the object, in addition to other objects created.

Arguments

object

object of class rtopVariogram or rtopVariogramCloud, or an object with class rtop that includes the sample variograms.

The object can also be of class SpatialPolygonsDataFrame or
SpatialPointsDataFrame with observations. If object is a
SpatialPointsDataFrame, it must have a column with name area.

observations

the observations, passed as a Spatial*DataFrame object, if object is an
rtopVariogram or rtopVariogramCloud

params

a set of parameters, used to modify the default parameters for the rtop package, set in getRtopParams. The argument params can also be used for the other methods, through the ...-argument.

dists

either a matrix with geostatistical distances (created by a call to the function gDist or a list with the areas discretized (from a call to rtopDisc.

mr

logical; defining whether the function should return a list with discretized elements and geostatistical distances, even if it was not called with an rtop-object as argument.

aOver

a matrix with the overlapping areas of the observations, used for computation of the nugget effect. It will normally be recomputed by the function if it is NULL and necessary

...

Other parameters to functions called from rtopFitVarigoram

Author

Jon Olav Skoien

References

Skoien J. O., R. Merz, and G. Bloschl. Top-kriging - geostatistics on stream networks. Hydrology and Earth System Sciences, 10:277-287, 2006.

Skoien, J. O. and G. Bloschl. Spatio-Temporal Top-Kriging of Runoff Time Series. Water Resources Research 43:W09419, 2007.

Skoien, J. O., Bloschl, G., Laaha, G., Pebesma, E., Parajka, J., Viglione, A., 2014. Rtop: An R package for interpolation of data with a variable spatial support, with an example from river networks. Computers & Geosciences, 67.

Examples

if (FALSE) {
library(rgdal)
rpath = system.file("extdata",package="rtop")
observations = readOGR(rpath,"observations")
# Create a column with the specific runoff:
observations$obs = observations$QSUMMER_OB/observations$AREASQKM
predictionLocations = readOGR(rpath,"predictionLocations")

# Setting some parameters 
params = list(gDist = TRUE, cloud = FALSE)
# Create a column with the specific runoff:
observations$obs = observations$QSUMMER_OB/observations$AREASQKM
# Build an object
rtopObj = createRtopObject(observations,predictionLocations, 
                           params = params)
# Fit a variogram (function also creates it)
rtopObj = rtopFitVariogram(rtopObj)
rtopObj$variogramModel
}