create a semivariogram matrix between a set of locations, or semivariogram matrices between and within two sets of locations
Description
varMat will create a semivariogram matrix between all the supports in a set of locations (observations or prediction locations) or semivariogram matrices between all the supports in one or two sets of locations, and also between them.
Usage
1 2 3 4 5 6 7 8 9 10 11 12  ## S3 method for class 'rtop'
varMat(object, varMatUpdate = FALSE, fullPred = FALSE, params = list(), ...)
## S3 method for class 'SpatialPolygonsDataFrame'
varMat(object, object2 = NULL,...)
## S3 method for class 'SpatialPolygons'
varMat(object, object2 = NULL, variogramModel,
overlapObs, overlapPredObs, ...)
## S3 method for class 'list'
varMat(object, object2 = NULL, coor1, coor2, maxdist = Inf,
variogramModel, diag = FALSE, sub1, sub2,
debug.level = 1, ...)

Arguments
object 
either: 1) an object of class 
varMatUpdate 
logical; if TRUE, also existing variance matrices will be recomputed, if FALSE, only missing variance matrices will be computed 
fullPred 
logical; whether to create the full covariance matrix also for the predictions, mainly used for simulations 
params 
a set of parameters, used to modify the default parameters for
the 
object2 
if 
variogramModel 
variogramModel to be used in calculation of the semivariogram matrix (matrices) 
... 
typical parameters to modify from the default parameters of the
rtoppackage (or modifications of the previously set parameters for the

overlapObs 
matrix with observations that overlap each other 
overlapPredObs 
matrix with 
coor1 
coordinates of centroids of 
coor2 
coordinates of centreofgravity of 
maxdist 
maximum distance between areas for inclusion in semivariogrma matrix 
diag 
logical; if TRUE only the semivariogram values along the diagonal will be calculated, typical for semivariogram matrix of prediction locations 
sub1 
semivariogram array for subtraction of inner variances of areas 
sub2 
semivariogram array for subtraction of inner variances of areas 
debug.level 
debug.level >= 1 will give output for every element 
Value
The lower level versions of the function calculates a semivariogram matrix
between locations in object
or between the locations in object
and the locations in object2
. The method for object of type rtop
calculates semivariogram matrices between observation locations, between prediction locations,
and between observation locations and prediction locations, and adds these
to object
.
Note
The argument varMatUpdate
is typically used to avoid repeated computations
of the same variance matrices. Default is FALSE, which will avoid recomputation
of the variance matrix for the observations if the procedure is crossvalidation
before interpolation. Should be set to TRUE if the variogram Model has been
changed, or if observation and/or prediction locations have been changed.
If an rtop
object contains observations and/or predictionLocations of type
STSDF
, the covariance matrix is computed based on the spatial
properties of the object.
Author(s)
Jon Olav Skoien
References
Skoien J. O., R. Merz, and G. Bloschl. Topkriging  geostatistics on stream networks. Hydrology and Earth System Sciences, 10:277287, 2006.
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.
See Also
gDist
Examples
1 2 3 4 5 6 7 8  ## Not run:
library(rgdal)
rpath = system.file("extdata",package="rtop")
observations = readOGR(rpath,"observations")
vmod = list(model = "Ex1", params = c(0.00001,0.007,350000,0.9,1000))
vm = varMat(observations, variogramModel = vmod)
## End(Not run)
