[R-sig-Geo] problem with enveloped test in spatstat

[David Unwin]

Many thanks.  It is a superb book and amazing value for money.  My only
excuse is that I have not as yet got to page 392.  Plotting the functions
also makes it a lot clearer.
Dave

On 21 April 2018 at 22:50, Marcelino de la Cruz Rot <
marcelino.delacruz at urjc.es> wrote:

> Hi David,
>
> This is very clearly explained in page 393 of Baddeley et al. 2015.
>
> Basically, the MAD test is affected by transformations of the summary
> function, with the L-function providing more powerful tests because of its
> stabilization of the variance.
>
> If you are interested in point pattern analysis I would recommend you to
> get a copy of this nice book.
>
>
> Cheers,
>
> Marcelino
>
>
> Adrian Baddeley, Ege Rubak, Rolf Turner (2015). Spatial Point Patterns:
> Methodology and Applications with R. London: Chapman and
>   Hall/CRC Press.
> http://www.crcpress.com/Spatial-Point-Patterns-Methodology-
> and-Applications-with-R/Baddeley-Rubak-Turner/9781482210200/
>
>
>
>
>
>
> El 21/04/2018 a las 18:05, David Unwin escribió:
>
>> Can any *spatstat* user explain to me why the two p-values obtained below
>> for an envelope test against CSR are so different?
>>
>>
>>
>> data(swedishpines)
>>> d<-swedishpines
>>> plot(d)
>>> mad.test(d,Kest,nsim=999,verbose=F)
>>>
>>
>>
>>          Maximum absolute deviation test of CSR
>>
>>          Monte Carlo test based on 999 simulations
>>
>>          Summary function: K(r)
>>
>>          Reference function: theoretical
>>
>>          Alternative: two.sided
>>
>>          Interval of distance values: [0, 24] units (one unit = 0.1
>> metres)
>>
>>          Test statistic: Maximum absolute deviation
>>
>>          Deviation = observed minus theoretical
>>
>>
>>
>> data:  d
>>
>> mad = 150.69, rank = 216, p-value = *0.216*
>>
>>
>>
>> mad.test(d,*Lest*,nsim=999,verbose=F)
>>>
>>
>>
>>          Maximum absolute deviation test of CSR
>>
>>          Monte Carlo test based on 999 simulations
>>
>>          Summary function: L(r)
>>
>>          Reference function: theoretical
>>
>>          Alternative: two.sided
>>
>>          Interval of distance values: [0, 24] units (one unit = 0.1
>> metres)
>>
>>          Test statistic: Maximum absolute deviation
>>
>>          Deviation = observed minus theoretical
>>
>>
>>
>> data:  d
>>
>> mad = 2.9921, rank = 9, p-value = *0.009*
>>
>>
>>
>> *!!!*
>>
>>
>>
>> These data are dispersed relative to CSR:
>>
>> kl<-envelope(d,Kest,nsim=999,correction="border")
>>> plot(kl)
>>>
>>
>> Dave Unwin
>>
>>         [[alternative HTML version deleted]]
>>
>> _______________________________________________
>> R-sig-Geo mailing list
>> R-sig-Geo at r-project.org
>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>> .
>>
>>
> --
> Marcelino de la Cruz Rot
> Depto. de Biología y Geología
> Física y Química Inorgánica
> Universidad Rey Juan Carlos
> Móstoles España
>
>


-- 


David J. Unwin
Professor Emeritus in Geography
Birkbeck, University of London
Phone  +44(0)1604 686526 Mobile: +44(0)7840 297239 (text preferred)
SKYPE: david.unwin99

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