R: Read Point Pattern From Data File

scanpp {spatstat.geom} | R Documentation

## Read Point Pattern From Data File

### Description

Reads a point pattern dataset from a text file.

### Usage

       scanpp(filename, window, header=TRUE, dir="", factor.marks=NULL, ...)

### Arguments

`filename` | String name of the file containing the coordinates of the points in the point pattern, and their marks if any.
`window` | Window for the point pattern. An object of class `"owin"`.
`header` | Logical flag indicating whether the first line of the file contains headings for the columns. Passed to `read.table`.
`dir` | String containing the path name of the directory in which `filename` is to be found. Default is the current directory.
`factor.marks` | Logical vector (or NULL) indicating whether marks are to be interpreted as factors. Defaults to `NULL` which means that strings will be interpreted as factors while numeric variables will not. See details.
`...` | Ignored.

### Details

This simple function reads a point pattern dataset from a file containing the cartesian coordinates of its points, and optionally the mark values for these points.

The file identified by `filename` in directory `dir` should be a text file that can be read using `read.table`. Thus, each line of the file (except possibly the first line) contains data for one point in the point pattern. Data are arranged in columns. There should be either two columns (for an unmarked point pattern) or more columns (for a marked point pattern).

If `header=FALSE` then the first two columns of data will be interpreted as the x and y coordinates of points. Remaining columns, if present, will be interpreted as containing the marks for these points.

If `header=TRUE` then the first line of the file should contain string names for each of the columns of data. If there are columns named `x` and `y` then these will be taken as the cartesian coordinates, and any remaining columns will be taken as the marks. If there are no columns named `x` and `y` then the first and second columns will be taken as the cartesian coordinates.

If a logical vector is provided for `factor.marks` the length should equal the number of mark columns (a shorter `factor.marks` is recycled to this length). This vector is then used to determine which mark columns should be interpreted as factors. Note: Strings will not be interpreted as factors if the corresponding entry in `factor.marks` is `FALSE`.

Note that there is intentionally no default for `window`. The window of observation should be specified. If you really need to estimate the window, use the Ripley-Rasson estimator `ripras`.

### Value

A point pattern (an object of class `"ppp"`, see `ppp.object`).

### Author(s)

Adrian Baddeley Adrian.Baddeley@curtin.edu.au and Rolf Turner r.turner@auckland.ac.nz.

### See Also

`ppp.object`, `ppp`, `as.ppp`, `ripras`

### Examples

      ##  files installed with spatstat, for demonstration
      d <- system.file("rawdata", "finpines", package="spatstat.data")
      if(nzchar(d)) {
        W <- owin(c(-5,5), c(-8,2))
        X <- scanpp("finpines.txt", dir=d, window=W)
        print(X)
      }
      d <- system.file("rawdata", "amacrine", package="spatstat.data")
      if(nzchar(d)) {
        W <- owin(c(0, 1060/662), c(0, 1))
        Y <- scanpp("amacrine.txt", dir=d, window=W, factor.marks=TRUE)
        print(Y)
      }

[Package spatstat.geom version 2.2-0 Index]