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.lst at 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,
Ant?nio 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
[[alternative HTML version deleted]]