Re: [R-sig-Geo] how to create several polygons from a list of vertices
Hi Vijay, Michael and Obrl
Thanks for the answers, finally I could do the job.
I learned a lot too!
Best regards
Antonio Olinto
Em Ter, 14 de ago de 2018 11:19 PM, Vijay Lulla
escreveu:
> Maybe you can try this then?
>
> polys <- SpatialPolygons(lapply(unique(vertices$cod),
> function(x) {
>Polygons(list(Polygon(vertices[vertices$cod ==
> x, 1:2])), ID=x)
> } ))
> HTH,
> Vijay.
>
> On Tue, Aug 14, 2018 at 6:03 PM Antonio Silva
> wrote:
>
>> Thanks Lulla,
>>
>> Nice solution. I could also export it as a shapefile after transforming
>> it to a spatial polygon dataframe.
>>
>> The problem is that I could not "individualize" the squares in a
>> multipart layer. They all have the same ID. I tried to change this without
>> success: "Single ID required".
>>
>> The attribute table of the shapefile should have 6 lines in my example
>> and not only one.
>>
>> Any other option?
>>
>> Thanks again,
>>
>> Antonio Olinto
>>
>>
>> Em ter, 14 de ago de 2018 às 18:10, Vijay Lulla
>> escreveu:
>>
>>> 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
>>> 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
[[alternative HTML version deleted]]
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>>>
>
> --
> Vijay Lulla
>
> Assistant Professor,
> Dept. of Geography, IUPUI
> 425 University Blvd, CA-207C.
> Indianapolis, IN-46202
> vlu...@iupui.edu
> ORCID: https://orcid.org/-0002-0823-2522
> Webpage: http://vijaylulla.com
>
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Re: [R-sig-Geo] how to create several polygons from a list of vertices
Here's another way with spbabel.
library(dplyr)
library(spbabel)
pts <-
tibble::tribble(~ID, ~x, ~y, ~grp,
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)
## objects and branches (parts) are the same level
## objects and branches (parts) are the same level
## and we maintain "grp" as the object attribute data
x <- pts %>% transmute(grp = grp, x_ = x, y_ = y,
object_ = grp, branch_ = grp,
order_ = ID, island_ = TRUE) %>% spbabel::sp()
On Wed, 15 Aug 2018 at 09:25 obrl soil wrote:
> Hi Antonio,
>
> have you tried with sf? Like:
>
> library(sf)
>
> pts <-
> tibble::tribble(~ID, ~x, ~y, ~grp,
>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)
>
> squares <- split(pts, pts$grp)
> squares <- lapply(squares, function(g) {
> # get just coords
> g <- as.matrix(g[, c(2,3)])
> # repeat first point last to close poly
> g <- rbind(g, g[1, ])
> # convert to an sf polygon object
> gp <- sf::st_polygon(list(g))
> # make sure the vertices are in an order
> # that complies with the simple
> # features standard
> gp <- sf::st_buffer(gp, 0L)
> })
> # turn list of polygons into geometry column
> squares_sfc <- sf::st_sfc(squares) # can add crs = ?? to this call
> # add an ID to make an sf data frame
> squares_sf <- sf::st_sf('ID' = seq(6), 'geometry' = squares_sfc)
>
> # if you still need to use sp for whatever reason
> squares_sp <- as(squares_sf, "Spatial")
>
> Regards,
> @obrl_soil
>
> On Wed, Aug 15, 2018 at 8:03 AM, Antonio Silva
> wrote:
> > Thanks Lulla,
> >
> > Nice solution. I could also export it as a shapefile after transforming
> it
> > to a spatial polygon dataframe.
> >
> > The problem is that I could not "individualize" the squares in a
> multipart
> > layer. They all have the same ID. I tried to change this without success:
> > "Single ID required".
> >
> > The attribute table of the shapefile should have 6 lines in my example
> and
> > not only one.
> >
> > Any other option?
> >
> > Thanks again,
> >
> > Antonio Olinto
> >
> >
> > Em ter, 14 de ago de 2018 às 18:10, Vijay Lulla
> > escreveu:
> >
> >> Maybe something like this?
> >>
> >> poly <- SpatialPolygons(list(Polygons(tapply(seq_len(nrow(vertices)),
> >> vertices$cod,
> >> function(x)
> >> Polygon(vertices[x,1:2])), ID="1")),
> >> proj4string=CRS("+proj=longlat +ellps=WGS84
> >> +datum=WGS84 +no_defs"))
> >>
> >>
> >> On Tue, Aug 14, 2018 at 4:17 PM Antonio Silva
> >> wrote:
> >>
> >>> Hi,
> >>>
> >>> I have a data.frame with the vertices (lon / lat) and codes from
> several
> >>> squares (more than 500 in the real dataset).
> >>> I want to create an object with these polygons (squares) and after this
> >>> export it as a shapefile.
> >>> With the script below I can draw one square.
> >>> library(sp)
> >>> P1 = Polygon(vertices[1:4,1:2])
> >>> Ps1 = SpatialPolygons(list(Polygons(list(P1), ID = "1")),
> >>> proj4string=CRS("+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs"))
> >>> plot(Ps1, axes = TRUE)
> >>>
> >>> Now I'm trying to create one object with all squares at once.
> >>> Is
Re: [R-sig-Geo] how to create several polygons from a list of vertices
Hi Antonio,
have you tried with sf? Like:
library(sf)
pts <-
tibble::tribble(~ID, ~x, ~y, ~grp,
1 , -33, -23,1,
2 , -32, -23,1,
3 , -32, -22,1,
4 , -33, -22,1,
5 , -32, -23,2,
6 , -31, -23,2,
7 , -31, -22,2,
8 , -32, -22,2,
9 , -31, -23,3,
10, -30, -23,3,
11, -30, -22,3,
12, -31, -22,3,
13, -33, -22,4,
14, -32, -22,4,
15, -32, -21,4,
16, -33, -21,4,
17, -32, -22,5,
18, -31, -22,5,
19, -31, -21,5,
20, -32, -21,5,
21, -31, -22,6,
22, -30, -22,6,
23, -30, -21,6,
24, -31, -21,6)
squares <- split(pts, pts$grp)
squares <- lapply(squares, function(g) {
# get just coords
g <- as.matrix(g[, c(2,3)])
# repeat first point last to close poly
g <- rbind(g, g[1, ])
# convert to an sf polygon object
gp <- sf::st_polygon(list(g))
# make sure the vertices are in an order
# that complies with the simple
# features standard
gp <- sf::st_buffer(gp, 0L)
})
# turn list of polygons into geometry column
squares_sfc <- sf::st_sfc(squares) # can add crs = ?? to this call
# add an ID to make an sf data frame
squares_sf <- sf::st_sf('ID' = seq(6), 'geometry' = squares_sfc)
# if you still need to use sp for whatever reason
squares_sp <- as(squares_sf, "Spatial")
Regards,
@obrl_soil
On Wed, Aug 15, 2018 at 8:03 AM, Antonio Silva wrote:
> Thanks Lulla,
>
> Nice solution. I could also export it as a shapefile after transforming it
> to a spatial polygon dataframe.
>
> The problem is that I could not "individualize" the squares in a multipart
> layer. They all have the same ID. I tried to change this without success:
> "Single ID required".
>
> The attribute table of the shapefile should have 6 lines in my example and
> not only one.
>
> Any other option?
>
> Thanks again,
>
> Antonio Olinto
>
>
> Em ter, 14 de ago de 2018 às 18:10, Vijay Lulla
> escreveu:
>
>> 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
>> 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
>>>
>>> [[alternative HTML version deleted]]
>>>
>>> ___
>>> R-sig-Geo mailing list
>>> R-sig-Geo@r-project.org
>>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>>
>>
>
> [[alternative HTML version deleted]]
>
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Re: [R-sig-Geo] how to create several polygons from a list of vertices
Thanks Lulla,
Nice solution. I could also export it as a shapefile after transforming it
to a spatial polygon dataframe.
The problem is that I could not "individualize" the squares in a multipart
layer. They all have the same ID. I tried to change this without success:
"Single ID required".
The attribute table of the shapefile should have 6 lines in my example and
not only one.
Any other option?
Thanks again,
Antonio Olinto
Em ter, 14 de ago de 2018 às 18:10, Vijay Lulla
escreveu:
> 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
> 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
>>
>> [[alternative HTML version deleted]]
>>
>> ___
>> R-sig-Geo mailing list
>> R-sig-Geo@r-project.org
>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>
>
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Re: [R-sig-Geo] how to create several polygons from a list of vertices
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 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
>
> [[alternative HTML version deleted]]
>
> ___
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> R-sig-Geo@r-project.org
> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>
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[R-sig-Geo] how to create several polygons from a list of vertices
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
[[alternative HTML version deleted]]
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