R: Examples for 'sf::st

### ** Examples

sfc = st_sfc(st_point(c(0,0)), st_point(c(1,1)))
sf = st_sf(a = 1:2, geom = sfc)
st_crs(sf) = 4326
st_geometry(sf)

Geometry set for 2 features 
Geometry type: POINT
Dimension:     XY
Bounding box:  xmin: 0 ymin: 0 xmax: 1 ymax: 1
Geodetic CRS:  WGS 84

POINT (0 0)

POINT (1 1)

sfc = st_sfc(st_point(c(0,0)), st_point(c(1,1)))
st_crs(sfc) = 4326
sfc

Geometry set for 2 features 
Geometry type: POINT
Dimension:     XY
Bounding box:  xmin: 0 ymin: 0 xmax: 1 ymax: 1
Geodetic CRS:  WGS 84

POINT (0 0)
POINT (1 1)

sfc = st_sfc(st_point(c(0,0)), st_point(c(1,1)))
sfc %>% st_set_crs(4326) %>% st_transform(3857)

Geometry set for 2 features 
Geometry type: POINT
Dimension:     XY
Bounding box:  xmin: 0 ymin: 0 xmax: 111319.5 ymax: 111325.1
Projected CRS: WGS 84 / Pseudo-Mercator

POINT (0 0)

POINT (111319.5 111325.1)

st_crs("EPSG:3857")$input

[1] "EPSG:3857"

st_crs(3857)$proj4string

[1] "+proj=merc +a=6378137 +b=6378137 +lat_ts=0 +lon_0=0 +x_0=0 +y_0=0 +k=1 +units=m +nadgrids=@null +wktext +no_defs"

pt = st_sfc(st_point(c(0, 60)), crs = 4326)
# st_axis_order() only has effect in GDAL >= 2.5.0:
st_axis_order() # query default: FALSE means interpret pt as (longitude latitude)

[1] FALSE

st_transform(pt, 3857)[[1]]

POINT (0 8399738)

old_value = FALSE
if (sf_extSoftVersion()["GDAL"] >= "2.5.0")
   (old_value = st_axis_order(TRUE))

[1] FALSE

# now interpret pt as (latitude longitude), as EPSG:4326 prescribes:
st_axis_order() # query current value

[1] TRUE

st_transform(pt, 3857)[[1]]

POINT (6679169 0)

st_axis_order(old_value) # set back to old value

Examples for 'sf::st_crs'

Retrieve coordinate reference system from object