Description Usage Arguments Details Value Author(s) References Examples
Perform a studentised permutation test for a difference between groups of point patterns.
1 2 3 4 
X 
Data. Either a 
formula 
Formula describing the grouping, when 
summaryfunction 
Summary function applicable to point patterns. 
... 
Additional arguments passed to 
rinterval 
Interval of distance values r over which the
summary function should be evaluated and over which the test
statistic will be integrated. If 
nperm 
Number of random permutations for the test. 
use.Tbar 
Logical value indicating choice of test statistic.
If 
minpoints 
Minimum permissible number of points in a point pattern for inclusion in the test calculation. 
rsteps 
Number of discretisation steps in the 
r 
Optional vector of distance values as the argument for

arguments.in.data 
Logical. If 
This function performs the studentized permutation test of Hahn (2012) for a difference between groups of point patterns.
The first argument X
should be either
Each element of X
will be interpreted as a group of
point patterns, assumed to be replicates of the same point process.
One column of the hyperframe should contain point patterns,
and another column should contain a factor indicating the
grouping. The argument formula
should be a formula in the
R language specifying the grouping: it should be of the form
P ~ G
where P
is the name of the column of point
patterns, and G
is the name of the factor.
A group needs to contain at least two point patterns with at least
minpoints
points in each pattern.
The function returns an object of class "htest"
and "studpermutest"
that can be printed and plotted.
The printout shows the test result and pvalue.
The plot shows the summary functions for the
groups (and the group means if requested).
Object of class "studpermutest"
.
Ute Hahn.
Modified for spatstat
by
\adrian
and \ege
Hahn, U. (2012) A studentized permutation test for the comparison of spatial point patterns. Journal of the American Statistical Association 107 (498), 754–764.
1 2 3  np < if(interactive()) 99 else 19
testpyramidal < studpermu.test(pyramidal, Neurons ~ group, nperm=np)
testpyramidal

Loading required package: nlme
Loading required package: rpart
spatstat 1.510 (nickname: 'Poetic Licence')
For an introduction to spatstat, type 'beginner'
Note: spatstat version 1.510 is out of date by more than 14 weeks; a newer version should be available.
Warning message:
5 patterns have been discarded because they contained fewer than 20 points
Studentized permutation test for grouped point patterns
Neurons ~ group
3 groups: control, schizoaffective, schizophrenic
summary function: Kest, evaluated on r in [0, 0.25]
test statistic: T, 19 random permutations
data: pyramidal
T = 2.3992, pvalue = 0.1
alternative hypothesis: not the same Kfunction
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