[R] loop with date

Tagmarie Ramgad82 at gmx.net
Tue Nov 27 17:25:53 CET 2012


Ok, sorry, I thought the more complex details might be confusing and nobody
might answer. 
Here is something which looks more like my real dataframe and also what I
want to do with it: 

That's my data frame: 

myframe <- data.frame (Timestamp=c("24.09.2012 09:00", "24.09.2012 10:00",
"24.09.2012 11:00", 
                                   "25.09.2012 09:00", "25.09.2012 10:00",
"25.09.2012 11:00"), 
                        Hunger=c(1,1,2,5,1,6) ,
                        Longitude=c(8.91617, 8.92700, 8.92711, 8.92722,
8.92733, 8.92744),
                        Latitude=c(54.5485, 54.5410, 54.5412, 54.5413,
54.5414, 54.5424) ,
                        AnimalID= c(rep("Ernie")))                                                        
head(myframe)
myframestime <- as.POSIXct (strptime(as.character(myframe$Timestamp),
"%d.%m.%Y %H:%M"), tz="GMT")
myframe2 <- cbind (myframe,myframestime)
myframe2$Timestamp <- NULL  
myframesxy <- project(cbind(myframe2$Longitude,myframe2$Latitude),"+proj=utm
+zone=32 +ellps=WGS84")
colnames(myframesxy) <- c("Long", "Lat")
myframe3 <- cbind(myframe2, myframesxy)
myframe3$Longitude <- NULL
myframe3$Latitude <- NULL
myframe3

And here is what I want to do with it (make an ltraj element, calculate the
brownian bridge homerange and get the kernel area of it - I take the 95
level): 

library(adehabitatHR)
myframe3ltraj <- as.ltraj(myframesxy,myframestime,  id=myframe3$AnimalID)
myframeLiker <- liker (myframe3ltraj, sig2=18, rangesig1=c(1,10) )
myframeLiker
MyframeBB <- kernelbb(myframe3ltraj, sig1=4.6036, sig2=18)
kernel.area(MyframeBB, unout=c("km2")    ) 

With the only difference that I don't want to calculate the homerange for
the complete time but for each day. 
 I could use "subset" and do it for every day by hand. 
But I'd have to do it for three month and then again for several animals. So
I thought using a loop for each animal to get the results by date would be
much faster. 
Does anybody have any idea? 





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