LISTAfunct: Product density LISTA functions

Description Usage Arguments Details Value Author(s) References Examples

Description

Computes an edge-corrected kernel estimator of the product density LISTA functions.

Usage

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LISTAfunct(xyt, s.region, t.region, ds, dt, ks = "epanech", hs,
  kt = "epanech", ht, correction = TRUE)

Arguments

xyt

Spatial-temporal coordinates (x,y,t) of the point pattern.

s.region

A two-column matrix specifying a polygonal region containing all data locations. If s.region is missing, the Ripley-Rasson estimate convex spatial domain is considered.

t.region

vector containing the minimum and maximum values of the time interval. If t.region is missing, the range of xyt[,3] is considered.

ds

A vector of distances u at which ρ^{(2)i}(u,v) is computed.

dt

A vector of distances v at which ρ^{(2)i}(u,v) is computed.

ks

A kernel function for the spatial distances. The default is "epanech" the Epanechnikov kernel. It can also be "box" kernel, or "biweight".

hs

A bandwidth of the kernel function ks.

kt

A kernel function for the temporal distances. The default is "epanech" the Epanechnikov kernel. It can also be "box" kernel, or "biweight".

ht

A bandwidth of the kernel function kt.

correction

It is TRUE by default and the Ripley's isotropic edge-correction weights are computed. If it is FALSE the estimated is without edge-correction.

Details

An individual product density LISTA functions ρ^{(2)i}(.,.) should reveal the extent of the contribution of the event (u_i,t_i) to the global estimator of the second-order product density ρ^{(2)}(.,.), and may provide a further description of structure in the data (e.g., determining events with similar local structure through dissimilarity measures of the individual LISTA functions), for more details see Cressie and Collins (2001).

Value

A list containing:

Author(s)

Francisco J. Rodriguez-Cortes <cortesf@uji.es> https://fjrodriguezcortes.wordpress.com

References

Baddeley, A. and Turner, J. (2005). spatstat: An R Package for Analyzing Spatial Point Pattens. Journal of Statistical Software 12, 1-42.

Cressie, N. and Collins, L. B. (2001). Analysis of spatial point patterns using bundles of product density LISA functions. Journal of Agricultural, Biological, and Environmental Statistics 6, 118-135.

Cressie, N. and Collins, L. B. (2001). Patterns in spatial point locations: Local indicators of spatial association in a minefield with clutter Naval Research Logistics (NRL), John Wiley & Sons, Inc. 48, 333-347.

Stoyan, D. and Stoyan, H. (1994). Fractals, random shapes, and point fields: methods of geometrical statistics. Chichester: Wiley.

Examples

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## Not run:
#################

# Realisations of the homogeneous spatio-temporal Poisson processes
stp <- rpp(100)$xyt
# Generated spatio-temporal point pattern
plot(stp)

# Estimation of product density LISTA functions
out <- LISTAfunct(stp)

# Randomly selected point and its product density LISTA 
ep <-sample(1:length(stp[,1]),1)
z1 <- out$hlista[,,ep]

# Spatio-temporal LISTA surface
par(mfrow=c(1,1))
persp(out$ds,out$dt,z1,theta=-45,phi=30,zlim=range(z1,na.rm=TRUE),expand=0.7,ticktype="detailed",xlab="r = distance",ylab="t = time",zlab="",cex.axis=0.7, cex.lab=0.7)
contour(out$ds,out$dt,z1,drawlabels=TRUE,axes=TRUE,xlab="r = distance",ylab="t = time",cex.axis=0.7, cex.lab=0.7)

## End(Not run)
#################

frajaroco/pdLISTA documentation built on May 16, 2019, 1:53 p.m.