R: Convert Data to a Point Pattern on a Linear Network

as.lpp {spatstat.linnet} | R Documentation

## Convert Data to a Point Pattern on a Linear Network

### Description

Convert various kinds of data to a point pattern on a linear network.

### Usage

      as.lpp(x=NULL, y=NULL, seg=NULL, tp=NULL, ...,
             marks=NULL, L=NULL, check=FALSE, sparse)

### Arguments

`x,y` | Vectors of cartesian coordinates, or any data acceptable to `xy.coords`. Alternatively `x` can be a point pattern on a linear network (object of class `"lpp"`) or a planar point pattern (object of class `"ppp"`).
`seg,tp` | Optional local coordinates. Vectors of the same length as `x,y`. See Details.
`...` | Ignored.
`marks` | Optional marks for the point pattern. A vector or factor with one entry for each point, or a data frame or hyperframe with one row for each point.
`L` | Linear network (object of class `"linnet"`) on which the points lie.
`check` | Logical. Whether to check the validity of the spatial coordinates.
`sparse` | Optional logical value indicating whether to store the linear network data in a sparse matrix representation or not. See `linnet`.

### Details

This function converts data in various formats into a point pattern on a linear network (object of class `"lpp"`).

The possible formats are:

- `x` is already a point pattern on a linear network (object of class `"lpp"`). Then `x` is returned unchanged.

- `x` is a planar point pattern (object of class `"ppp"`). Then `x` is converted to a point pattern on the linear network `L` using `lpp`.

- `x,y,seg,tp` are vectors of equal length. These specify that the `i`th point has Cartesian coordinates `(x[i],y[i])`, and lies on segment number `seg[i]` of the network `L`, at a fractional position `tp[i]` along that segment (with `tp=0` representing one endpoint and `tp=1` the other endpoint of the segment).

- `x,y` are missing and `seg,tp` are vectors of equal length as described above.

- `seg,tp` are `NULL`, and `x,y` are data in a format acceptable to `xy.coords` specifying the Cartesian coordinates.

- Only the arguments `x` and `L` are given, and `x` is a data frame with one of the following types:

  - two columns labelled `seg,tp` interpreted as local coordinates on the network.

  - two columns labelled `x,y` interpreted as Cartesian coordinates.

  - four columns labelled `x,y,seg,tp` interpreted as Cartesian coordinates and local coordinates.

### Value

A point pattern on a linear network (object of class `"lpp"`).

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au

and Rolf Turner r.turner@auckland.ac.nz

### See Also

`lpp`.

### Examples

       A <- as.psp(simplenet)
       X <- runifpointOnLines(10, A)
       is.ppp(X)
       Y <- as.lpp(X, L=simplenet)

[Package spatstat.linnet version 2.3-1 Index]