R: Quadrature Scheme on a Linear Network

linequad {spatstat} | R Documentation

## Quadrature Scheme on a Linear Network

### Description

Generates a quadrature scheme (an object of class `"quad"`) on a linear network.

### Usage

    linequad(X, Y, ..., eps = NULL, nd = 1000, random = FALSE)

### Arguments

`X` | Data points. An object of class `"lpp"` or `"ppp"`.
`Y` | Line segments on which the points of `X` lie. An object of class `"psp"`. Required only when `X` is a `"ppp"` object.
`...` | Ignored.
`eps` | Optional. Spacing between successive dummy points along each segment.
`nd` | Optional. Total number of dummy points to be generated.
`random` | Logical value indicating whether the sequence of dummy points should start at a randomly-chosen position along each segment.

### Details

This command generates a quadrature scheme (object of class `"quad"`) from a pattern of points on a linear network.

Normally the user does not need to call `linequad` explicitly. It is invoked by spatstat functions when needed. A quadrature scheme is required by `lppm` in order to fit point process models to point pattern data on a linear network. A quadrature scheme is also used by `rhohat.lpp` and other functions.

In order to create the quadrature scheme, dummy points are placed along each line segment of the network. The dummy points are evenly-spaced with spacing `eps`. The default is `eps = totlen/nd` where `totlen` is the total length of all line segments in the network.

### Value

A quadrature scheme (object of class `"quad"`).

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au, Greg McSwiggan and Suman Rakshit.

### See Also

`lppm`

[Package spatstat version 1.54-0 Index]