rgdal: showWKT – R documentation

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showWKT

Show Well-Known Text spatial reference system metadata

Description

In modern workflows with PROJ >= 6 and GDAL >= 3, use only showSRID() DEPRECATED: Use GDAL/OGR spatial reference objects to convert a PROJ.4 representation to a Well-Known Text representation, and report an EPSG code if it can be determined by OGR SRS services.

Usage

showWKT(p4s, file = NULL, morphToESRI = FALSE, enforce_xy = NULL)
showP4(wkt, morphFromESRI=FALSE, enforce_xy = NULL)
showEPSG(p4s, enforce_xy = NULL)
showSRID(inSRID, format="WKT2", multiline="NO", enforce_xy = NULL, EPSG_to_init=TRUE,
 prefer_proj=NULL)
get_P6_datum_hard_fail()
set_P6_datum_hard_fail(value)
get_thin_PROJ6_warnings()
set_thin_PROJ6_warnings(value)
get_prefer_proj()
set_prefer_proj(value)
get_rgdal_show_exportToProj4_warnings()
set_rgdal_show_exportToProj4_warnings(value)
get_PROJ6_warnings_count()
OSRIsProjected(obj)

Arguments

`p4s`	A valid PROJ.4 string representing a spatial reference system
`file`	if not NULL, a file name to which the output Well-Known Text representation should be written
`morphToESRI`	default FALSE, morph the WKT string to the representation used by ESRI; set FALSE by default 2020-03-04 to avoid occasional Windows crashes seen when passing a very modern WKT string to an old version of PROJ: https://github.com/edzer/sp/issues/75
`enforce_xy`	(PROJ6+/GDAL3+) either use global setting (default NULL) or override policy for coordinate ordering easting/x as first axis, northing/y as second axis.
`wkt`	A valid WKT character string representing a spatial reference system
`morphFromESRI`	default TRUE, morph the WKT string from the representation used by ESRI
`inSRID`	Input coordinate reference string
`obj`	valid CRS object
`format`	Output format, default WKT2
`multiline`	Multiline output, either `"NO"` or `"YES"`
`EPSG_to_init`	default TRUE, workaround for PROJ 6.3.0 frailty leading to the dropping of +ellps= and +units=; DATUM seems to disappear in the internal definition
`prefer_proj`	default NULL, if TRUE, use PROJ compiled code directly, rather than FALSE using PROJ via GDAL SRS; if NULL, uses value shown by `get_prefer_proj()` set on startup to TRUE.

value

a logical value. For set_P6_datum_hard_fail(): by default, a deprecated/ignored input DATUM key/value pair on reading a file with PROJ6 will give a warning (default FALSE); if TRUE, an error is triggered, which may be trapped using try. For set_thin_PROJ6_warnings() default FALSE, can be set to TRUE to report only once and count the number of non-issues warnings, retrieved by get_PROJ6_warnings_count(). For set_rgdal_show_exportToProj4_warnings(), default in rgdal version 1.5.* TRUE, from 1.6 FALSE. The options("rgdal_show_exportToProj4_warnings"="x") may be used before loading rgdal to set the internal logical variables; if the option is set to "all", all warnings reporting CRS degradation stemming from the GDAL OSR function exportToProj4() even if trivial are reported; if set to "thin", all warnings are detected but thinned so that one report is given per function call; if set to "none", the degradations are detected but not reported.

Value

For showWKT, a character string containing the WKT representation of the PROJ.4 string.

Note

The options("rgdal_show_exportToProj4_warnings"="x") may be used before loading rgdal to set the internal logical variables; if the option is set to "all", all warnings reporting CRS degradation stemming from the GDAL OSR function exportToProj4() even if trivial are reported; if set to "thin", all warnings are detected but thinned so that one report is given per function call; if set to "none", the degradations are detected but not reported.

Author(s)

Roger Bivand

References

https://gdal.org/tutorials/osr_api_tut.html

Examples

set_thin_PROJ6_warnings(TRUE)
cities <- readOGR(system.file("vectors", package = "rgdal")[1], "cities")
readLines(system.file("vectors/cities.prj", package = "rgdal")[1])
showWKT(proj4string(cities))
showWKT("+init=epsg:28992")
showP4(showWKT("+init=epsg:28992"))
showEPSG("+proj=utm +zone=30")
showEPSG("+proj=longlat +ellps=WGS84")
exts <- rgdal_extSoftVersion()
run <- new_proj_and_gdal()
if (run) {
  cat(showSRID("EPSG:27700", multiline="YES"), "\n")
}
if (run) {
(prj <- showSRID("EPSG:27700", "PROJ"))
}
if (run) {
showSRID(paste0(prj, " +datum=OSGB36"), "WKT1")
}
if (run) {
showSRID(paste0(prj, " +towgs84=370.936,-108.938,435.682"), "WKT1")
}
if (run) {
showSRID(paste0(prj, " +nadgrids=OSTN15_NTv2_OSGBtoETRS.gsb"), "WKT1")
}
if (run) {
showSRID(paste0(prj, " +datum=OSGB36"), "WKT2")
}
if (run) {
showSRID(paste0(prj, " +towgs84=370.936,-108.938,435.682"), "WKT2")
}
if (run) {
showSRID(paste0(prj, " +nadgrids=OSTN15_NTv2_OSGBtoETRS.gsb"), "WKT2")
}
if (run) {
showSRID("ESRI:102761", "WKT2")
}
if (run) {
showSRID("OGC:CRS84", "WKT2")
}
if (run) {
showSRID("urn:ogc:def:crs:OGC:1.3:CRS84", "WKT2")
}
if (run) {
try(showSRID("", "WKT2"))
}

OSRIsProjected(CRS("+proj=longlat"))
OSRIsProjected(CRS("+proj=geocent"))
OSRIsProjected(CRS("+proj=geocent +units=km"))

rgdal

Bindings for the 'Geospatial' Data Abstraction Library

v1.5-23

GPL (>= 2)

Authors

Roger Bivand [cre, aut] (<https://orcid.org/0000-0003-2392-6140>), Tim Keitt [aut], Barry Rowlingson [aut, ctb], Edzer Pebesma [ctb], Michael Sumner [ctb], Robert Hijmans [ctb], Daniel Baston [ctb], Even Rouault [cph, ctb], Frank Warmerdam [cph, ctb], Jeroen Ooms [ctb], Colin Rundel [ctb]

Initial release

2021-02-03