[R-sig-Geo] Filtering a set of points in a "ppp" object by distance using marks

[ASANTOS]

Hi Marcelino,

Thanks, I just make a little change in your code:

ddd <- nndist(insects.ppp, by=factor(insects.ppp$marks))
subset(insects.ppp,  marks=="termiNests" & ddd[,"antNests"] >20)

I put `ddd[,"antNests"] >20` despite `ddd[,"termiNests"] >20` because I 
need "termiNests" mark far 20 units to each "antNests"

Best wishes,

Alexandre

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Alexandre dos Santos
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Em 16/09/2020 03:18, Marcelino de la Cruz Rot escreveu:
> Hi Alexandre,
>
> may be this?
>
>
> ddd <- nndist(insects.ppp, by=factor(insects.ppp$marks))
> subset(insects.ppp,  marks=="termiNests" & ddd[,"termiNests"] >20)
>
>
> Cheers,
>
> Marcelino
>
>
> El 15/09/2020 a las 22:52, ASANTOS via R-sig-Geo escribió:
>> Dear R-Sig-Geo Members,
>>
>> I'd like to find any way to filtering a set of points in a "ppp" 
>> object by minimum distance just only between different marks. In my 
>> example:
>>
>> #Package
>> library(spatstat)
>>
>> #Point process example - ants
>> data(ants)
>> ants.ppp<-ppp(x=ants$x,y=ants$y,marks=rep("antNests",length(ants$x)),window=Window(ants)) 
>>
>>
>>
>> # Create a artificial point pattern - termites
>> termites <- rpoispp(0.0005, win=Window(ants))
>> termites.ppp<-ppp(x=termites$x,y=termites$y,marks=rep("termiNests",length(termites$x)),window=Window(ants)) 
>>
>>
>>
>> #Join ants.ppp and termites.ppp
>> insects.ppp<-superimpose(ants.ppp,termites.ppp)
>>
>>
>> #If I try to use subset function:
>>
>> subset(insects.ppp, pairdist(insects.ppp) > 20 & marks=="termiNests")
>>
>> #Marked planar point pattern: 223 points #marks are of storage type
>> �character� #window: polygonal boundary #enclosing rectangle: [-25, 803]
>> x [-49, 717] units (one unit = 0.5 feet) #Warning message: #In ppp(X[,
>> 1], X[, 2], window = win, marks = marx, check = check) : # 70751 out of
>> 70974 points had NA or NaN coordinate values, and were discarded
>>
>> Not the desirable result yet, because I'd like to calculate just only 
>> the > 20 "termiNests" to "antNests" marks and not the "termiNests" 
>> with "termiNests" too.
>>
>> Please any ideas?
>>
>> Thanks in advanced,
>>
>