sf (version 0.8-0)

st_write: Write simple features object to file or database

Description

Write simple features object to file or database

Usage

st_write(obj, dsn, layer, ...)
# S3 method for sfc
st_write(obj, dsn, layer, ...)
# S3 method for sf
st_write(obj, dsn, layer = NULL, ...,
  driver = guess_driver_can_write(dsn), dataset_options = NULL,
  layer_options = NULL, quiet = FALSE, factorsAsCharacter = TRUE,
  update = driver %in% db_drivers, delete_dsn = FALSE,
  delete_layer = FALSE, fid_column_name = NULL)
# S3 method for data.frame
st_write(obj, dsn, layer = NULL, ...)
write_sf(..., quiet = TRUE, delete_layer = TRUE)
# S4 method for PostgreSQLConnection,character,sf
dbWriteTable(conn, name,
  value, ..., row.names = FALSE, overwrite = FALSE, append = FALSE,
  field.types = NULL, factorsAsCharacter = TRUE, binary = TRUE)
# S4 method for DBIObject,character,sf
dbWriteTable(conn, name, value, ...,
  row.names = FALSE, overwrite = FALSE, append = FALSE,
  field.types = NULL, factorsAsCharacter = TRUE, binary = TRUE)

Arguments

obj

object of class sf or sfc

dsn

data source name (interpretation varies by driver - for some drivers, dsn is a file name, but may also be a folder or contain a database name) or a Database Connection (currently official support is for RPostgreSQL connections)

layer

layer name (varies by driver, may be a file name without extension); if layer is missing, the basename of dsn is taken.

...

other arguments passed to dbWriteTable when dsn is a Database Connection

driver

character; name of driver to be used; if missing and dsn is not a Database Connection, a driver name is guessed from dsn; st_drivers() returns the drivers that are available with their properties; links to full driver documentation are found at http://www.gdal.org/ogr_formats.html.

dataset_options

character; driver dependent dataset creation options; multiple options supported.

layer_options

character; driver dependent layer creation options; multiple options supported.

quiet

logical; suppress info on name, driver, size and spatial reference

factorsAsCharacter

logical; convert factor objects into character strings (default), else into numbers by as.numeric.

update

logical; FALSE by default for single-layer drivers but TRUE by default for database drivers as defined by db_drivers. For database-type drivers (e.g. GPKG) TRUE values will make GDAL try to update (append to) the existing data source, e.g. adding a table to an existing database, or adding records to a layer. See also the next two arguments and Details.

delete_dsn

logical; delete data source dsn before attempting to write?

delete_layer

logical; delete layer layer before attempting to write?

fid_column_name

character, name of column with feature IDs; if specified, this column is no longer written as feature attribute.

conn

DBIObject

name

character vector of names (table names, fields, keywords).

value

a data.frame.

row.names

Add a row.name column, or a vector of length nrow(obj) containing row.names; default FALSE.

overwrite

Will try to drop table before writing; default FALSE.

append

Append rows to existing table; default FALSE.

field.types

default NULL. Allows to override type conversion from R to PostgreSQL. See dbDataType() for details.

binary

Send geometries serialized as Well-Known Binary (WKB); if FALSE, uses Well-Known Text (WKT). Defaults to TRUE (WKB).

Value

obj, invisibly; in case obj is of class sfc, it is returned as an sf object.

Details

Columns (variables) of a class not supported are dropped with a warning.

When updating an existing layer, records are appended to it if the updating object has the right variable names and types. If names don't match an error is raised. If types don't match, behaviour is undefined: GDAL may raise warnings or errors or fail silently.

When deleting layers or data sources is not successful, no error is emitted. delete_dsn and delete_layers should be handled with care; the former may erase complete directories or databases.

See Also

st_drivers

Examples

# NOT RUN {
nc = st_read(system.file("shape/nc.shp", package="sf"))
st_write(nc, paste0(tempdir(), "/", "nc.shp"))
st_write(nc, paste0(tempdir(), "/", "nc.shp"), delete_layer = TRUE) # overwrites
data(meuse, package = "sp") # loads data.frame from sp
meuse_sf = st_as_sf(meuse, coords = c("x", "y"), crs = 28992)
# writes X and Y as columns:
st_write(meuse_sf, paste0(tempdir(), "/", "meuse.csv"), layer_options = "GEOMETRY=AS_XY") 
st_write(meuse_sf, paste0(tempdir(), "/", "meuse.csv"), layer_options = "GEOMETRY=AS_WKT",
  delete_dsn=TRUE) # overwrites
# }
# NOT RUN {
 library(sp)
 example(meuse, ask = FALSE, echo = FALSE)
 try(st_write(st_as_sf(meuse), "PG:dbname=postgis", "meuse_sf",
     layer_options = c("OVERWRITE=yes", "LAUNDER=true")))
 demo(nc, ask = FALSE)
 try(st_write(nc, "PG:dbname=postgis", "sids", layer_options = "OVERWRITE=true"))
# }