Maybe something like this?
poly <- SpatialPolygons(list(Polygons(tapply(seq_len(nrow(vertices)),
vertices$cod,
function(x)
Polygon(vertices[x,1:2])), ID="1")),
proj4string=CRS("+proj=longlat +ellps=WGS84
+datum=WGS84 +no_defs"))
On Tue, Aug 14, 2018 at 4:17 PM Antonio Silva <aolinto....@gmail.com> wrote:
> Hi,
>
> I have a data.frame with the vertices (lon / lat) and codes from several
> squares (more than 500 in the real dataset).
> I want to create an object with these polygons (squares) and after this
> export it as a shapefile.
> With the script below I can draw one square.
> library(sp)
> P1 = Polygon(vertices[1:4,1:2])
> Ps1 = SpatialPolygons(list(Polygons(list(P1), ID = "1")),
> proj4string=CRS("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"))
> plot(Ps1, axes = TRUE)
>
> Now I'm trying to create one object with all squares at once.
> Is it possible?
>
> Thanks a lot,
>
> Antônio Olinto
>
> sample data:vertices
> lon lat cod
> 1 -33 -23 1
> 2 -32 -23 1
> 3 -32 -22 1
> 4 -33 -22 1
> 5 -32 -23 2
> 6 -31 -23 2
> 7 -31 -22 2
> 8 -32 -22 2
> 9 -31 -23 3
> 10 -30 -23 3
> 11 -30 -22 3
> 12 -31 -22 3
> 13 -33 -22 4
> 14 -32 -22 4
> 15 -32 -21 4
> 16 -33 -21 4
> 17 -32 -22 5
> 18 -31 -22 5
> 19 -31 -21 5
> 20 -32 -21 5
> 21 -31 -22 6
> 22 -30 -22 6
> 23 -30 -21 6
> 24 -31 -21 6
>
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>
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