[R] build a SpatialLines object from a list

Ashraf Afana asafaneh at yahoo.com
Tue Sep 26 11:36:12 CEST 2017

Hi Eric,

Thanks for the help.But this will not solve the problem as it will generate a list and what I need is an object of class sp using SpatialLine function from sp package.So, I need to convert each matrix to coordinates and then to a line and then to a spatial line as figured in the code.

My data structure is a list of 141 matrices.Each matrix represents coordinates of the river lines position.

Ashraf, cheers 

    On Monday, 25 September 2017, 16:56, Eric Berger <ericjberger at gmail.com> wrote:

 Hi Ashraf,It is not obvious to me what your structures are but one problem in your function is the assignment tt1 <- SpatialLines(list(tt[[i]])).
This will set tt1 to just have one item.
Consider the following
test.func <- function(x) {    tt1 <- list()    for ( i in ... )  {       ...       tt1[[i]] <- SpatialLines(tt[[i]])    }    return(tt1)}

On Mon, Sep 25, 2017 at 3:40 PM, Ashraf Afana via R-help <r-help at r-project.org> wrote:

Hi all,I'm trying to build a SpatialLines object from a list that contains 124 river segments. Each segment in the list contains the x,y coordinates. I'm using the following code to create the SpatialLines object, but it just retrieves one segment. Any suggestions?

test.func = function(x){
     for (i in 1:length(x)) {        tt[[i]] <- x[i]; tt[[i]]  = Line(tt[[i]]); tt[[i]]  = Lines(list(tt[[i]] ), 'i')        tt1 = SpatialLines(list(tt[[i]]))           }    return(tt1)  }
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