infline {spatstat.geom} | R Documentation |
Infinite Straight Lines
Description
Define the coordinates of one or more straight lines in the plane
Usage
infline(a = NULL, b = NULL, h = NULL, v = NULL, p = NULL, theta = NULL)
## S3 method for class 'infline'
print(x, ...)
## S3 method for class 'infline'
plot(x, ...)
Arguments
a , b |
Numeric vectors of equal length giving the
intercepts |
h |
Numeric vector giving the positions of horizontal lines when
they cross the |
v |
Numeric vector giving the positions of vertical lines when
they cross the |
p , theta |
Numeric vectors of equal length
giving the polar coordinates of the line.
Incompatible with |
x |
An object of class |
... |
Extra arguments passed to |
Details
The class infline
is a convenient way to handle
infinite straight lines in the plane.
The position of a line can be specified in several ways:
-
its intercept
and slope
in the equation
can be used unless the line is vertical.
-
for vertical lines we can use the position
where the line crosses the
axis
-
for horizontal lines we can use the position
where the line crosses the
axis
-
the polar coordinates
and
can be used for any line. The line equation is
The command infline
will accept line coordinates in any
of these formats. The arguments a,b,h,v
have the same interpretation
as they do in the line-plotting function
abline
.
The command infline
converts between different coordinate
systems (e.g. from a,b
to p,theta
) and returns an
object of class "infline"
that contains a representation of the lines in
each appropriate coordinate system. This object can be printed
and plotted.
Value
The value of infline
is an object of class "infline"
which is basically a data frame with columns a,b,h,v,p,theta
.
Each row of the data frame represents one line.
Entries may be NA
if a coordinate is not applicable to
a particular line.
Author(s)
Adrian Baddeley Adrian.Baddeley@curtin.edu.au and Rolf Turner rolfturner@posteo.net.
See Also
rotate.infline
,
clip.infline
,
chop.tess
,
whichhalfplane
Examples
infline(a=10:13,b=1)
infline(p=1:3, theta=pi/4)
plot(c(-1,1),c(-1,1),type="n",xlab="",ylab="", asp=1)
plot(infline(p=0.4, theta=seq(0,pi,length=20)))