st_transform_proj: Transform or convert coordinates of simple features directly...

In lwgeom: Bindings to Selected 'liblwgeom' Functions for Simple Features

Transform or convert coordinates of simple features directly with Proj.4 (bypassing GDAL)

Description

Transform or convert coordinates of simple features directly with Proj.4 (bypassing GDAL)

Usage

st_transform_proj(x, crs, ...)

## S3 method for class 'sfc'
st_transform_proj(x, crs, ...)

## S3 method for class 'sf'
st_transform_proj(x, crs, ...)

## S3 method for class 'sfg'
st_transform_proj(x, crs, ...)

Arguments

x	object of class sf, sfc or sfg
crs	character; target CRS, or, in case of a length 2 character vector, source and target CRS
...	ignored

Details

Transforms coordinates of object to new projection, using PROJ directly rather than the GDAL API used by st_transform.

If crs is a single CRS, it forms the target CRS, and in that case the source CRS is obtained as st_crs(x). Since this presumes that the source CRS is accepted by GDAL (which is not always the case), a second option is to specify the source and target CRS as two proj4strings in argument crs. In the latter case, st_crs(x) is ignored and may well be NA.

The st_transform_proj method for sfg objects assumes that the CRS of the object is available as an attribute of that name.

Examples

library(sf)
p1 = st_point(c(7,52))
p2 = st_point(c(-30,20))
sfc = st_sfc(p1, p2, crs = 4326)
sfc
st_transform_proj(sfc, "+proj=wintri")
library(sf)
nc = st_read(system.file("shape/nc.shp", package="sf"))
st_transform_proj(nc[1,], "+proj=wintri +over")
st_transform_proj(structure(p1, proj4string = "+init=epsg:4326"), "+init=epsg:3857")

lwgeom documentation built on May 29, 2024, 9:40 a.m.