Generate a projection string.

Input any accepted format of 'PROJ' coordinate reference system specification. Return value is a string in the requested format.

proj_crs_text(source, format = 0L)

Arguments

source

input projection specification one of ('PROJ4', 'WKT2', 'EPSG', 'PROJJSON', ... see the library documentation link in Details)

format

integer, 0 for 'WKT', 1 for 'PROJ', 2 for 'PROJJSON'

Value

character string in requested format

Details

This function requires PROJ version 6.0 or higher to be useful. If not, this function simply returns 'NA'.

See the library documentation for details on input and output formats.

warning

Note that a PROJ string is not a full specification, in particular this means that a string like "+proj=laea" cannot be converted to full WKT, because it is technically a transformation step not a crs. To get the full WKT form use a string like "+proj=laea +type=crs".

Examples

cat(proj_crs_text("EPSG:4326", format = 0L))
#> GEOGCRS["WGS 84",
#>     ENSEMBLE["World Geodetic System 1984 ensemble",
#>         MEMBER["World Geodetic System 1984 (Transit)"],
#>         MEMBER["World Geodetic System 1984 (G730)"],
#>         MEMBER["World Geodetic System 1984 (G873)"],
#>         MEMBER["World Geodetic System 1984 (G1150)"],
#>         MEMBER["World Geodetic System 1984 (G1674)"],
#>         MEMBER["World Geodetic System 1984 (G1762)"],
#>         MEMBER["World Geodetic System 1984 (G2139)"],
#>         ELLIPSOID["WGS 84",6378137,298.257223563,
#>             LENGTHUNIT["metre",1]],
#>         ENSEMBLEACCURACY[2.0]],
#>     PRIMEM["Greenwich",0,
#>         ANGLEUNIT["degree",0.0174532925199433]],
#>     CS[ellipsoidal,2],
#>         AXIS["geodetic latitude (Lat)",north,
#>             ORDER[1],
#>             ANGLEUNIT["degree",0.0174532925199433]],
#>         AXIS["geodetic longitude (Lon)",east,
#>             ORDER[2],
#>             ANGLEUNIT["degree",0.0174532925199433]],
#>     USAGE[
#>         SCOPE["Horizontal component of 3D system."],
#>         AREA["World."],
#>         BBOX[-90,-180,90,180]],
#>     ID["EPSG",4326]]
proj_crs_text("EPSG:4326", format = 1L)
#> [1] "+proj=longlat +datum=WGS84 +no_defs +type=crs"
south55 <- "+proj=utm +zone=55 +south +ellps=GRS80 +units=m +no_defs +type=crs"
proj_crs_text(proj_crs_text(south55), 1L)
#> [1] "+proj=utm +zone=55 +south +ellps=GRS80 +units=m +no_defs +type=crs"