Type: Package
Title: Extension to 'spatstat' for Large Datasets on a Linear Network
Version: 3.1-2
Date: 2024-09-05
Depends: R (≥ 3.5.0), spatstat.data (≥ 3.1-0), spatstat.sparse (≥ 3.1-0), spatstat.univar (≥ 3.0-0), spatstat.geom (≥ 3.3-0), spatstat.random (≥ 3.3-0), spatstat.explore (≥ 3.3-0), spatstat.model (≥ 3.3-0), spatstat.linnet (≥ 3.2-0), spatstat (≥ 3.1-1)
Imports: spatstat.utils (≥ 3.0-5), Matrix
Maintainer: Adrian Baddeley <Adrian.Baddeley@curtin.edu.au>
Description: Extension to the 'spatstat' family of packages, for analysing large datasets of spatial points on a network. The geometrically- corrected K function is computed using a memory-efficient tree-based algorithm described by Rakshit, Baddeley and Nair (2019).
License: GPL-2 | GPL-3 [expanded from: GPL (≥ 2)]
NeedsCompilation: yes
ByteCompile: true
Packaged: 2024-09-05 07:36:23 UTC; adrian
Author: Suman Rakshit ORCID iD [aut, cph], Adrian Baddeley ORCID iD [cre, cph]
Repository: CRAN
Date/Publication: 2024-09-05 14:50:02 UTC

Extension to 'spatstat' for Large Datasets on a Linear Network

Description

Extension to the 'spatstat' family of packages, for analysing large datasets of spatial points on a network. The geometrically- corrected K function is computed using a memory-efficient tree-based algorithm described by Rakshit, Baddeley and Nair (2019).

Details

This is an extension to the spatstat package for the analysis of large data sets on linear networks.

Its main functionality is a memory-efficient algorithm for computing the estimate of the K function on a linear network, described in Rakshit et al (2019).

The main functions are Knet and Knetinhom. These are counterparts of the functions linearK and linearKinhom in the spatstat.linnet package.

The spatstat.linnet functions linearK and linearKinhom are usable (and slightly faster) for small datasets, but require substantial amounts of memory. For larger datasets, the functions Knet and Knetinhom are much more efficient.

The DESCRIPTION file:

Package: spatstat.Knet
Type: Package
Title: Extension to 'spatstat' for Large Datasets on a Linear Network
Version: 3.1-2
Date: 2024-09-05
Depends: R (>= 3.5.0), spatstat.data (>= 3.1-0), spatstat.sparse (>= 3.1-0), spatstat.univar (>= 3.0-0), spatstat.geom (>= 3.3-0), spatstat.random (>= 3.3-0), spatstat.explore (>= 3.3-0), spatstat.model (>= 3.3-0), spatstat.linnet (>= 3.2-0), spatstat (>= 3.1-1)
Imports: spatstat.utils (>= 3.0-5), Matrix
Authors@R: c(person(given="Suman", family="Rakshit", role = c("aut", "cph"), email = "suman.rakshit@curtin.edu.au", comment=c(ORCID="0000-0003-0052-128X")), person(given="Adrian", family="Baddeley", role = c("cre", "cph"), email = "Adrian.Baddeley@curtin.edu.au", comment = c(ORCID="0000-0001-9499-8382")))
Maintainer: Adrian Baddeley <Adrian.Baddeley@curtin.edu.au>
Description: Extension to the 'spatstat' family of packages, for analysing large datasets of spatial points on a network. The geometrically- corrected K function is computed using a memory-efficient tree-based algorithm described by Rakshit, Baddeley and Nair (2019).
License: GPL (>= 2)
NeedsCompilation: yes
ByteCompile: true
Author: Suman Rakshit [aut, cph] (<https://orcid.org/0000-0003-0052-128X>), Adrian Baddeley [cre, cph] (<https://orcid.org/0000-0001-9499-8382>)

Index of help topics:

Knet                    Geometrically-Corrected K Function on Network
Knetinhom               Geometrically-Corrected Inhomogeneous K
                        Function on Network
spatstat.Knet-package   Extension to 'spatstat' for Large Datasets on a
                        Linear Network
wacrashes               Road Accidents in Western Australia

Author(s)

Suman Rakshit [aut, cph] (<https://orcid.org/0000-0003-0052-128X>), Adrian Baddeley [cre, cph] (<https://orcid.org/0000-0001-9499-8382>)

Maintainer: Adrian Baddeley <Adrian.Baddeley@curtin.edu.au>

References

Rakshit, S., Baddeley, A. and Nair, G. (2019) Efficient code for second order analysis of events on a linear network. Journal of Statistical Software 90 (1) 1–37. DOI: 10.18637/jss.v090.i01


Geometrically-Corrected K Function on Network

Description

Compute the geometrically-corrected K function for a point pattern on a linear network.

Usage

Knet(X, r = NULL, freq, ..., verbose=FALSE)

Arguments

X

Point pattern on a linear network (object of class "lpp").

r

Optional. Numeric vector of values of the function argument r. There is a sensible default.

freq

Vector of frequencies corresponding to the point events on the network. The length of this vector should be equal to the number of points on the network. The default frequency is one for every point on the network.

...

Ignored.

verbose

A logical for printing iteration number corresponding to each point event on the network.

Details

This command computes the geometrically-corrected K function, proposed by Ang et al (2012), from point pattern data on a linear network. The algorithm used in this computation is discussed in Rakshit et al (2019).

The spatstat function linearK is usable (and slightly faster) for the same purpose for small datasets, but requires substantial amounts of memory. For larger datasets, the function Knet is much more efficient.

Value

Function value table (object of class "fv").

Author(s)

Suman Rakshit (modified by Adrian Baddeley)

References

Ang, Q.W., Baddeley, A. and Nair, G. (2012) Geometrically corrected second-order analysis of events on a linear network, with applications to ecology and criminology. Scandinavian Journal of Statistics 39, 591–617.

Rakshit, S., Baddeley, A. and Nair, G. (2019) Efficient code for second order analysis of events on a linear network. Journal of Statistical Software 90 (1) 1–37. DOI: 10.18637/jss.v090.i01

Examples

   UC <- unmark(chicago)
   r <- seq(0, 1000, length = 41)
   K <- Knet(UC, r = r)

Geometrically-Corrected Inhomogeneous K Function on Network

Description

Compute the geometrically-corrected inhomogeneous K function for a point pattern on a linear network.

Usage

Knetinhom(X, lambda, r = NULL, freq, ..., verbose=FALSE)

Arguments

X

Point pattern on a linear network (object of class "lpp").

lambda

Fitted intensity of the point process. Either a numeric vector giving values of the fitted intensity at each data point of X, or an object of class "linim", "linfun" or "lppm" from which the fitted intensity at each data point can be extracted.

r

Optional. Numeric vector of values of the function argument r. There is a sensible default.

freq

Vector of frequencies corresponding to the point events on the network. The length of this vector should be equal to the number of points on the network. The default frequency is one for every point on the network.

...

Ignored.

verbose

Logical value indicating whether to print progress reports during the computation.

Details

This command computes the inhomogeneous version of the geometrically-corrected K function, proposed by Ang et al (2012), from point pattern data on a linear network.

The algorithm used in this computation is described in Rakshit et al (2019).

The spatstat function linearKinhom is usable (and slightly faster) for this purpose for small datasets, but requires substantial amounts of memory. For larger datasets, the function Knetinhom is much more efficient.

Value

Function value table (object of class "fv").

Author(s)

Suman Rakshit (modified by Adrian Baddeley)

References

Ang, Q.W., Baddeley, A. and Nair, G. (2012) Geometrically corrected second-order analysis of events on a linear network, with applications to ecology and criminology. Scandinavian Journal of Statistics 39, 591–617.

Rakshit, S., Baddeley, A. and Nair, G. (2019) Efficient code for second order analysis of events on a linear network. Journal of Statistical Software 90 (1) 1–37. DOI: 10.18637/jss.v090.i01

Examples

   UC <- unmark(chicago)
   fit <- lppm(UC ~ x+y)
   r <- seq(0, 1000, length = 41)
   K <- Knetinhom(UC, lambda=fit, r = r)

Road Accidents in Western Australia

Description

This dataset gives the spatial locations of all road accidents recorded in the state of Western Australia for the year 2011, on the state road network.

These data were published and analysed in Rakshit et al (2019).

Usage

data(wacrashes)

Format

A object of class "lpp" representing the spatial point pattern of accident locations on the network of roads in Western Australia.

Details

The road network has 88,512 intersections and 115,169 road segments. The spatial coordinates are expressed in metres, and the total network length is 97,165,540 metres (97,165 km). The number of accident locations on the network is 14,562.

Source

Main Roads, Western Australia. Made available as part of the Western Australian Whole of Government Open Data Policy.

References

Rakshit, S., Baddeley, A. and Nair, G. (2019) Efficient code for second order analysis of events on a linear network. Journal of Statistical Software 90 (1) 1–37. DOI: 10.18637/jss.v090.i01

Examples

  data(wacrashes)
  wacrashes
  summary(wacrashes)
  plot(wacrashes, cols="red", cex=0.5)