deconvPointVgm {atakrig}

Point-scale variogram, cross-variogram deconvolution.

Description

Point-scale variogram, cross-variogram deconvolution.

Usage

deconvPointVgm(x, model = "Exp", maxIter = 100,
    fixed.range = NA, longlat = FALSE, maxSampleNum = 100, fig = TRUE, ...)
deconvPointCrossVgm(x, y, xPointVgm, yPointVgm, model = "Exp",
    maxIter = 100, fixed.range = NA, longlat = FALSE,
    maxSampleNum = 100, fig = TRUE, ...)
deconvPointVgmForCoKriging(x, model = "Exp", maxIter = 100,
    fixed.range = NA, maxSampleNum = 100, fig = TRUE, ...)

Arguments

x, y

for deconvPointVgm and deconvPointCrossVgm, x is a discreteArea object.

for deconvPointVgmForCoKriging, x is a list of discreteArea objects of all variables.

xPointVgm, yPointVgm

point-scale variograms of x and y respectively, gstat variogramModel.

model

commonly used variogram models supported, "Exp" for exponential model, "Sph" for spherical model, "Gau" for gaussian model.

maxIter

max iteration number of deconvolution.

fixed.range

a fixed variogram range for deconvoluted point-scale variogram.

longlat

indicator whether coordinates are longitude/latitude.

maxSampleNum

to save memory and to reduce calculation time, for large number of discretized areas, a number (maxSampleNum) of random sample will be used. The samples are collected by system sampling method.

fig

whether to plot deconvoluted variogram.

...

additional paramters passed to autofitVgm.

Details

The deconvolution algorithm is implemented according to Pierre Goovaerts, Math. Geosci., 2008, 40: 101-128.

Value

pointVariogram

deconvoluted point variogram.

areaVariogram

fitted area variogram from area centroids.

experientialAreaVariogram

experiential area variogram from area centroids.

regularizedAreaVariogram

regularized area variogram from discretized area points and point variogram.

References

Goovaerts, P., 2008. Kriging and semivariogram deconvolution in the presence of irregular geographical units. Mathematical Geosciences 40 (1): 101-128.

See Also

ataKriging,ataCoKriging

Examples

library(atakrig)
library(terra)

rpath <- system.file("extdata", package="atakrig")
aod3k <- rast(file.path(rpath, "MOD04_3K_A2017042.tif"))

aod3k.d <- discretizeRaster(aod3k, 1500)
grid.pred <- discretizeRaster(aod3k, 1500, type = "all")

sv.ok <- deconvPointVgm(aod3k.d, model="Exp", ngroup=12, rd=0.8, fig = FALSE)
#pred.ataok <- ataKriging(aod3k.d, grid.pred, sv.ok, showProgress = FALSE)


library(atakrig)
library(sf)

## load demo data from rtop package
#if (!require("rtop", quietly = TRUE)) message("rtop library is required for demo data.")
rpath <- system.file("extdata", package="rtop")
observations <- read_sf(rpath, "observations")

## point-scale variogram
obs.discrete <- discretizePolygon(observations, cellsize=1500, id="ID", value="obs")
pointsv <- deconvPointVgm(obs.discrete, model="Exp", ngroup=12, rd=0.75, fig=TRUE)