[R-sig-Geo] Change Lines'IDs within a SpatialLines object

[marta azores]

Ok, I didn't know that. Your suggestion it works well.
Thanks for your answer


Marta

2017-02-07 16:26 GMT-01:00 Roger Bivand <Roger.Bivand at nhh.no>:

> On Tue, 7 Feb 2017, marta azores wrote:
>
> Hello everyone,
>>
>> I would like to change the ID of SpatialLinesDataFrame (SLDF), by the
>> value
>> of one variable (in my case splndf$Idkey).
>>
>> I read the answer of Roger Bivand in this link:
>> https://stat.ethz.ch/pipermail/r-sig-geo/2015-December/023809.html
>>
>> This works well when I write an specific number. However, I can't change
>> the id of my SLDF by my Idkey value.
>>
>> At first the value in the SLDF was an integer and I converted to a numeric
>> value. I don't understand why works with a number and not when I define
>> the
>> number from the SLDF.
>> Any idea?
>>
>
> The values contained in row.names() of data.frame objects and similar are
> always seen as being of type character. Consequently, if you try to assign
> a vector of type numeric, it will fail.
>
> Never, ever use @ - these are exclusively for programming internally. Use
> splndf$Idkey, which is its accessor method. Either use
> as.character(splndf$Idkey), or possibly formatC(splndf$Idkey, format="d",
> flag="0", width=<>) for left-padding of zeros to your choice of width if
> the column is integer but should be like "0010", and integer 10 is stored.
>
> Roger
>
>
>> Thanks in advance,
>>
>> Marta
>> #######################################################################
>> ##script
>>
>> ########change the ID's SLDF
>>
>> #Please use row.names(), so here:
>> row.names(L1) <- c("c", "d")
>> #If L1 was a SpatialLinesDataFrame, the row.names of the data slot would
>> also
>> #be updated.
>> ###################################################
>> row.names(splndf)
>> #[1] "1"
>>
>> #1) First, I try manually to change the id (works)
>> row.names(splndf) <- ("2905")
>> str(splndf)#@ ID   : chr "2905"
>> str(2905)
>> #num 2905
>> is.numeric(2905)
>> 2905
>> #2) Second, I try extract the Idkey value and convert into the SLDF's ID.
>> k<-splndf at data$Idkey
>> str(k)
>> #int 2905
>> k <- as.numeric(k)
>> k
>> #[1] 2905
>> str(k)
>> # num 2905
>> is.numeric(k)
>> #TRUE
>> k
>> row.names(splndf) <- (k)
>> #Error in (function (classes, fdef, mtable)  :
>> #unable to find an inherited method for function ‘spChFIDs’ for signature
>> ‘"SpatialLinesDataFrame", "numeric"’
>>
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>>
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>>
>
> --
> Roger Bivand
> Department of Economics, Norwegian School of Economics,
> Helleveien 30, N-5045 Bergen, Norway.
> voice: +47 55 95 93 55; e-mail: Roger.Bivand at nhh.no
> http://orcid.org/0000-0003-2392-6140
> https://scholar.google.no/citations?user=AWeghB0AAAAJ&hl=en
> http://depsy.org/person/444584

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