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create point density raster OR other ways to thin point data

Marcelino de la Cruz 
Hi,

you can combine density.ppp and rthin to thin inversely to the density 
of points. See this example

# example of a heterogeneous point pattern
library(spatstat)
data(lansing)
maple<-lansing[lansing$marks=="maple"]
plot(maple)
maple.dens<- density(maple)
plot(maple.dens)

# get the probability of retention as inversely proportional to the 
density

maple.p <- eval.im(1-(maple.dens/max(maple.dens)))
plot(maple.p)

# Thin your pp
plot(rthin(maple, maple.p))

Sigma us calculted by default by density.ppp but you can set your aown 
sigma also (see the help page of density.ppp)


HTH,
Marcelino

El 2013-02-24 19:38, Julie Lee-Yaw escribi?:

  
    

      
      
    

  


  


  


  
  

    

  

    
      
    
    
Thread (3 messages)

  

  

    
            
        Julie Lee-Yaw
        
        create point density raster OR other ways to thin point data
      
      Feb 24
    
    
      
            
        Marcelino de la Cruz
        
        create point density raster OR other ways to thin point data
      
      Feb 24
    
    
      
            
        Robert J. Hijmans
        
        create point density raster OR other ways to thin point data
      
      Feb 24