Flip geometries horizontally or vertically — ddbs

Flips (reflects) geometries around the centroid. Returns the result as an sf object or creates a new table in the database. This function is equivalent to terra::flip().

Usage

ddbs_flip(
  x,
  direction = c("horizontal", "vertical"),
  by_feature = FALSE,
  conn = NULL,
  name = NULL,
  crs = NULL,
  crs_column = "crs_duckspatial",
  overwrite = FALSE,
  quiet = FALSE
)

Arguments

x: An sf spatial object. Alternatively, it can be a string with the name of a table with geometry column within the DuckDB database conn. Data is returned from this object.
direction: character string specifying the flip direction: "horizontal" (default) or "vertical". Horizontal flips across the Y-axis (left-right), vertical flips across the X-axis (top-bottom)
by_feature: Logical. If TRUE, the geometric operation is applied separately to each geometry. If FALSE (default), the geometric operation is applied to the data as a whole.
conn: A connection object to a DuckDB database. If NULL, the function runs on a temporary DuckDB database.
name: A character string of length one specifying the name of the table, or a character string of length two specifying the schema and table names. If NULL (the default), the function returns the result as an sf object
crs: The coordinates reference system of the data. Specify if the data doesn't have a crs_column, and you know the CRS.
crs_column: a character string of length one specifying the column storing the CRS (created automatically by ddbs_write_vector). Set to NULL if absent.
overwrite: Boolean. whether to overwrite the existing table if it exists. Defaults to FALSE. This argument is ignored when name is NULL.
quiet: A logical value. If TRUE, suppresses any informational messages. Defaults to FALSE.

Value

an sf object or TRUE (invisibly) for table creation

Examples

if (FALSE) { # \dontrun{
## load packages
library(duckspatial)
library(sf)

# create a duckdb database in memory (with spatial extension)
conn <- ddbs_create_conn(dbdir = "memory")

## read data
argentina_sf <- st_read(system.file("spatial/argentina.geojson", package = "duckspatial"))

## store in duckdb
ddbs_write_vector(conn, argentina_sf, "argentina")

## flip all features together as a whole (default)
ddbs_flip(conn = conn, "argentina", direction = "horizontal", by_feature = FALSE)

## flip each feature independently
ddbs_flip(conn = conn, "argentina", direction = "horizontal", by_feature = TRUE)

## flip without using a connection
ddbs_flip(argentina_sf, direction = "horizontal")
} # }