Quadrature Scheme on a Linear Network
Generates a quadrature scheme (an object of class
on a linear network.
linequad(X, Y, …, eps = NULL, nd = 1000, random = FALSE)
Data points. An object of class
Line segments on which the points of
Xlie. An object of class
"psp". Required only when
Optional. Spacing between successive dummy points along each segment. (This is the maximum spacing; some spacings will be shorter.)
Optional. Total number of dummy points to be generated. (Actual number may be larger.)
Logical value indicating whether the sequence of dummy points should start at a randomly-chosen position along each segment.
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
It is invoked by spatstat functions when needed.
A quadrature scheme is required by
in order to fit point process models to point pattern data on a linear
network. A quadrature scheme is also used by
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.
Every line segment of the network will contain at least one dummy
point. Consequently the actual number of dummy points generated
will typically be greater than
nd is small.
eps is specified, the
number of dummy points will be greater than
eps is large.
A quadrature scheme (object of class