Ldot {spatstat} | R Documentation |
Calculates an estimate of the multitype L-function
(from type i
to any type)
for a multitype point pattern.
Ldot(X, i, ...)
X |
The observed point pattern, from which an estimate of the dot-type L function Lij(r) will be computed. It must be a multitype point pattern (a marked point pattern whose marks are a factor). See under Details. |
i |
Number or character string identifying the type (mark value)
of the points in X from which distances are measured.
|
... |
Arguments passed to Kdot .
|
This command computes
Li.(r) = sqrt(Ki.(r)/pi)
where Ki.(r) is the multitype K-function
from points of type i
to points of any type.
See Kdot
for information
about Ki.(r).
The command Ldot
first calls
Kdot
to compute the estimate of the i
-to-any
K-function, and then applies the square root transformation.
For a marked Poisson point process,
the theoretical value of the L-function is
Li.(r) = r.
The square root also has the effect of stabilising
the variance of the estimator, so that L_{i\bullet}
{Li.}
is more appropriate
for use in simulation envelopes and hypothesis tests.
An object of class "fv"
, see fv.object
,
which can be plotted directly using plot.fv
.
Essentially a data frame containing columns
r |
the vector of values of the argument r at which the function Li. has been estimated |
theo |
the theoretical value Li.(r) = r for a stationary Poisson process |
together with columns named
"border"
, "bord.modif"
,
"iso"
and/or "trans"
,
according to the selected edge corrections. These columns contain
estimates of the function Li.
obtained by the edge corrections named.
Adrian Baddeley adrian@maths.uwa.edu.au http://www.maths.uwa.edu.au/~adrian/ and Rolf Turner r.turner@auckland.ac.nz
data(amacrine) L <- Ldot(amacrine, "off") plot(L)