[R-sig-Geo] Clip a SpatialLinesDataFrame

[Robert J. Hijmans]

Jim
You can try

library(raster)
x <- crop(roads, polygons)

Robert

On Fri, Jul 10, 2015 at 11:17 AM, Jim Burke <javajimburke at gmail.com> wrote:
> Clipping a SpatialLinesDataFrame by an envelope "SpatialPolygons" results
> in a bare bones "SpatialLines" with no "@data" slot. The "out" file is a
> roads file which plots fine but has no road names available.
>
> My question is how to restore nontopogical attribute information, such as
> "@data", from the original large SpatialLinesDataFrame? .
>
> in_df <-readOGR(dsn="new.shp", layer="new", verbose = TRUE)
> env = gEnvelope( neighborhood_sp, byid=FALSE, id = NULL)  # neighborhood_sp
> is class "SpatialPolygonsDataFrame"
> out <- gIntersection(in_df, env, byid=TRUE) #works quite quickly
>
> Additional information
>
> The out class "SpatialLines"
>> getSLLinesIDSlots(out)
>    [1] "3239 1"   "3240 1"   "3543 1"   "7405 1"   "7406 1"   "7407 1"
>    [7] "7408 1"   "7409 1"   "7410 1"   "7411 1"   "7412 1"   "7413 1"
>   [13] "7424 1"   "7425 1"   "7426 1"   "7427 1"   "7428 1"   "7429 1"
>> str(out)
> Formal class 'SpatialLines' [package "sp"] with 3 slots
>   ..@ lines      :List of 5870
>   .. ..$ :Formal class 'Lines' [package "sp"] with 2 slots
>   .. .. .. ..@ Lines:List of 1
>   .. .. .. .. ..$ :Formal class 'Line' [package "sp"] with 1 slot
>   .. .. .. .. .. .. ..@ coords: num [1:5, 1:2] 2499508 2499546 2499545
> 2499542 2499540 ...
>   .. .. .. .. .. .. .. ..- attr(*, "dimnames")=List of 2
>   .. .. .. .. .. .. .. .. ..$ : NULL
>   .. .. .. .. .. .. .. .. ..$ : chr [1:2] "x" "y"
>   .. .. .. ..@ ID   : chr "3239 1"
>   .. ..$ :Formal class 'Lines' [package "sp"] with 2 slots
>   .. .. .. ..@ Lines:List of 1
>   .. .. .. .. ..$ :Formal class 'Line' [package "sp"] with 1 slot
>   .. .. .. .. .. .. ..@ coords: num [1:2, 1:2] 2499506 2499508 7023664
> 7023801
>
> The in_df class "SpatialLinesDataFrame"
>> head(In_df at data, n = 12)
>     DC_ID Prefix Pretype        Name Type Suffix           Class
>  Label
> 0  843772   <NA>    <NA>    Freeport Pkwy   <NA>  Minor Arterial  Freeport
> Pkwy
> 1  843773   <NA>    <NA>    Freeport Pkwy   <NA>  Minor Arterial  Freeport
> Pkwy
> 2  844139   <NA>    STHY         183 <NA>      E Primary Highway    Airport
> Fwy
>
> Let me know if you want additional information.
>
> Thanks in advance
> Jim Burke
>
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>
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