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

In rtop: Interpolation of Data with Variable Spatial Support

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 class 'rtop'
rtopFitVariogram(object, params = list(), iprint = 0, ...) 
## S3 method for class 'SpatialPolygonsDataFrame'
rtopFitVariogram(object, params=list(), ...) 
## S3 method for class 'SpatialPointsDataFrame'
rtopFitVariogram(object, params=list(), ...) 
## S3 method for class 'rtopVariogram'
rtopFitVariogram(object, observations, dists = NULL, 
                    params=list(), mr = FALSE, aOver = NULL, iprint = 0, ...) 
## S3 method for class 'rtopVariogramCloud'
rtopFitVariogram(object, observations, dists = NULL, 
                    aOver = NULL, params=list(), mr = FALSE, iprint = 0, ...) 

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
iprint	print flag that is passed to sceua
...	Other parameters to functions called from rtopFitVarigoram. For the three first methods of the function, ... can also include parameters to the last two methods.

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.

Note

There are several options for fitting of the variogramModel, where the parameters can be set in params, which is a list of parameters for modification of the default parameters of the rtop-package given in a call to getRtopParams. The first choice is between individual fitting and binned fitting. This is based on the type of variogram submitted, individual fitting is done if a cloud variogram (of class rtopVariogramCloud) is passed as argument, and binned fitting if the submitted variogram is of class rtopVariogram. If the function is called with an object of class rtop, having both variogram and variogramCloud among its arguments, the variogram model is fitted to the variogram which is consistent with the parameter cloud.

Author(s)

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

rpath = system.file("extdata",package="rtop")
library(sf)
observations = st_read(rpath, "observations")
predictionLocations = st_read(rpath,"predictionLocations")

# Create a column with the specific runoff:
observations$obs = observations$QSUMMER_OB/observations$AREASQKM

# 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

rtop documentation built on July 4, 2024, 9:09 a.m.