sf (version 0.4-3)

sf: Create sf object

Description

Create sf, which extends data.frame-like objects with a simple feature list column

Usage

st_sf(..., agr = NA_agr_, row.names,
  stringsAsFactors = default.stringsAsFactors(), crs, precision,
  sf_column_name = NULL)
# S3 method for sf
[(x, i, j, ..., drop = FALSE, op = st_intersects)

Arguments

...

column elements to be binded into an sf object or a single list or data.frame with such columns; at least one of these columns shall be a geometry list-column of class sfc or be a list-column that can be converted into an sfc by st_as_sfc.

agr

character vector; see details below.

row.names

row.names for the created sf object

stringsAsFactors

logical; logical: should character vectors be converted to factors? The `factory-fresh' default is TRUE, but this can be changed by setting options(stringsAsFactors = FALSE).

crs

coordinate reference system: integer with the epsg code, or character with proj4string

precision

numeric; see st_as_binary

sf_column_name

character; name of the active list-column with simple feature geometries; in case there are more than one and sf_column_name is not given, the first one is taken.

x

object of class sf

i

record selection, see [.data.frame

j

variable selection, see [.data.frame

drop

logical, default FALSE; if TRUE drop the geometry column and return a data.frame, else make the geometry sticy and return a sf object.

op

function; geometrical binary predicate function to apply when i is a simple feature object

Details

agr, attribute-geometry-relationship, specifies for each non-geometry attribute column how it relates to the geometry, and can have one of following values: "constant", "aggregate", "identity". "constant" is used for attributes that are constant throughout the geometry (e.g. land use), "aggregate" where the attribute is an aggregate value over the geometry (e.g. population density or population count), "identity" when the attributes uniquely identifies the geometry of particular "thing", such as a building ID or a city name. The default value, NA_agr_, implies we don't know.

"[.sf" will return a data.frame if the geometry column (of class sfc) is dropped (drop=TRUE), an sfc object if only the geometry column is selected, otherwise returns an sf object; see also [.data.frame.

Examples

g = st_sfc(st_point(1:2))
st_sf(a=3,g)
st_sf(g, a=3)
st_sf(a=3, st_sfc(st_point(1:2))) # better to name it!
g = st_sfc(st_point(1:2), st_point(3:4))
s = st_sf(a=3:4, g)
s[1,]
class(s[1,])
s[,1]
class(s[,1])
s[,2]
class(s[,2])
g = st_sf(a=2:3, g)
pol = st_sfc(st_polygon(list(cbind(c(0,3,3,0,0),c(0,0,3,3,0)))))
h = st_sf(r = 5, pol)
g[h,]
h[g,]