DSpat (version 0.1.6)

weeds.lines: Transect lines from Dubbo weed data

Description

Lines sampled in a farming paddock with eight 150m wide transects (75m each side)

Usage

data(weeds.lines)

Format

A data frame with 8 observations on the following 6 variables.

label

Label of the transect 1 to 8

x0

x coordinate for the beginning of the line

x1

x coordinate for the end of the line

y0

y coordinate for the beginning of the line

y1

y coordinate for the end of the line

width

full width of the transect

Details

These are lines constructed for the weeds data that were provided by Melville and Welsh (see reference below) that were used in the Biometrics paper on distance sampling.

The code used to create the lines was as follows:

  weeds.lines=data.frame(label=1:8,x0=75+0:7*150,x1=75+0:7*150,
     y0=rep(0,8),y1=rep(1200,8),width=rep(149.9999,8))

The line widths were reduced by 0.0001 so the transects do no abut because spatstat treats them as overlapping polygons.

References

Melville, G. J., and A. H. Welsh. 2001. Line transect sampling in small regions. Biometrics 57:1130-1137.