The function quadrat.test is generic, with methods for
point patterns (class "ppp"), split point patterns
(class "splitppp") and point process models
(class "ppm").
If X is a split point pattern, then for each of the
component point patterns (taken separately) we test
the null hypotheses of Complete Spatial Randomness,
then combine the result into a single test.
The method quadrat.test.ppp is applied to each
component point pattern. Then the results are pooled using
pool.quadrattest to obtain a single test.