geojsonio (version 0.1.4)

geojson_write: Convert many input types with spatial data to a geojson file

Description

Convert many input types with spatial data to a geojson file

Usage

geojson_write(input, lat = NULL, lon = NULL, geometry = "point",
  group = NULL, file = "myfile.geojson", precision = NULL, ...)

Arguments

input

Input list, data.frame, or spatial class. Inputs can also be dplyr tbl_df class since it inherits from data.frame.

lat

(character) Latitude name. The default is NULL, and we attempt to guess.

lon

(character) Longitude name. The default is NULL, and we attempt to guess.

geometry

(character) One of point (Default) or polygon.

group

(character) A grouping variable to perform grouping for polygons - doesn't apply for points

file

(character) A path and file name (e.g., myfile), with the .geojson file extension. Default writes to current working directory.

precision

desired number of decimal places for the coordinates in the geojson file. Using fewer decimal places can decrease file sizes (at the cost of precision).

...

Further args passed on to writeOGR

See Also

geojson_list, geojson_json

Examples

# From a data.frame
## to points
geojson_write(us_cities[1:2,], lat='lat', lon='long')

## to polygons
head(states)
geojson_write(input=states, lat='lat', lon='long', geometry='group', group="group")

## partial states dataset to points (defaults to points)
geojson_write(input=states, lat='lat', lon='long')

## Lists
### list of numeric pairs
poly <- list(c(-114.345703125,39.436192999314095),
          c(-114.345703125,43.45291889355468),
          c(-106.61132812499999,43.45291889355468),
          c(-106.61132812499999,39.436192999314095),
          c(-114.345703125,39.436192999314095))
geojson_write(poly, geometry = "polygon")

### named list
mylist <- list(list(latitude=30, longitude=120, marker="red"),
               list(latitude=30, longitude=130, marker="blue"))
geojson_write(mylist)

# From a numeric vector of length 2
## Expected order is lon, lat
vec <- c(-99.74, 32.45)
geojson_write(vec)

## polygon from a series of numeric pairs
### this requires numeric class input, so inputting a list will
### dispatch on the list method
poly <- c(c(-114.345703125,39.436192999314095),
          c(-114.345703125,43.45291889355468),
          c(-106.61132812499999,43.45291889355468),
          c(-106.61132812499999,39.436192999314095),
          c(-114.345703125,39.436192999314095))
geojson_write(poly, geometry = "polygon")

# Write output of geojson_list to file
res <- geojson_list(us_cities[1:2,], lat='lat', lon='long')
class(res)
geojson_write(res)

# Write output of geojson_json to file
res <- geojson_json(us_cities[1:2,], lat='lat', lon='long')
class(res)
geojson_write(res)

# From SpatialPolygons class
library('sp')
poly1 <- Polygons(list(Polygon(cbind(c(-100,-90,-85,-100),
   c(40,50,45,40)))), "1")
poly2 <- Polygons(list(Polygon(cbind(c(-90,-80,-75,-90),
   c(30,40,35,30)))), "2")
sp_poly <- SpatialPolygons(list(poly1, poly2), 1:2)
geojson_write(sp_poly)

# From SpatialPolygonsDataFrame class
sp_polydf <- as(sp_poly, "SpatialPolygonsDataFrame")
geojson_write(input = sp_polydf)

# From SpatialGrid
x <- GridTopology(c(0,0), c(1,1), c(5,5))
y <- SpatialGrid(x)
geojson_write(y)

# From SpatialGridDataFrame
sgdim <- c(3,4)
sg <- SpatialGrid(GridTopology(rep(0,2), rep(10,2), sgdim))
sgdf <- SpatialGridDataFrame(sg, data.frame(val = 1:12))
geojson_write(sgdf)

# From SpatialRings
r1 <- Ring(cbind(x=c(1,1,2,2,1), y=c(1,2,2,1,1)), ID="1")
r2 <- Ring(cbind(x=c(1,1,2,2,1), y=c(1,2,2,1,1)), ID="2")
r1r2 <- SpatialRings(list(r1, r2))
geojson_write(r1r2)

# From SpatialRingsDataFrame
dat <- data.frame(id = c(1,2), value = 3:4)
r1r2df <- SpatialRingsDataFrame(r1r2, data = dat)
geojson_write(r1r2df)

# From SpatialPixels
library("sp")
pixels <- suppressWarnings(SpatialPixels(SpatialPoints(us_cities[c("long", "lat")])))
summary(pixels)
geojson_write(pixels)

# From SpatialPixelsDataFrame
library("sp")
pixelsdf <- suppressWarnings(
 SpatialPixelsDataFrame(points = canada_cities[c("long", "lat")], data = canada_cities)
)
geojson_write(pixelsdf)

# From SpatialCollections
library("sp")
poly1 <- Polygons(list(Polygon(cbind(c(-100,-90,-85,-100), c(40,50,45,40)))), "1")
poly2 <- Polygons(list(Polygon(cbind(c(-90,-80,-75,-90), c(30,40,35,30)))), "2")
poly <- SpatialPolygons(list(poly1, poly2), 1:2)
coordinates(us_cities) <- ~long+lat
dat <- SpatialCollections(points = us_cities, polygons = poly)
geojson_write(dat)