# projinfo¶

New in version 6.0.0.

Geodetic object and coordinate operation queries

## Synopsis¶

projinfo
[-o formats] [-k crs|operation|ellipsoid] [–summary] [-q]
[[–area name_or_code] | [–bbox west_long,south_lat,east_long,north_lat]]
[–spatial-test contains|intersects]
[–crs-extent-use none|both|intersection|smallest]
[–pivot-crs always|if_no_direct_transformation|never|{auth:code[,auth:code]*}]
[–boundcrs-to-wgs84]
[–main-db-path path] [–aux-db-path path]*
[–identify]
[–c-ify] [–single-line]
{object_definition} | {object_reference} | (-s {srs_def} -t {srs_def})

where {object_definition} or {srs_def} is

{object_reference} is a filename preceded by the ‘@’ character. The file referenced by the {object_reference} must contain a valid {object_definition}.

## Description¶

projinfo is a program that can query information on a geodetic object, coordinate reference system (CRS) or coordinate operation, when the -s and -t options are specified, and display it under different formats (PROJ string, WKT string or PROJJSON string).

It can also be used to query coordinate operations available between two CRS.

The program is named with some reference to the GDAL gdalsrsinfo that offers partly similar services.

The following control parameters can appear in any order:

-o formats

formats is a comma separated combination of: all, default, PROJ, WKT_ALL, WKT2_2015, WKT2_2018, WKT1_GDAL, WKT1_ESRI, PROJJSON.

Except all and default, other formats can be preceded by - to disable them.

-k crs|operation|ellipsoid

When used to query a single object with a AUTHORITY:CODE, determines the (k)ind of the object in case there are CRS, coordinate operations or ellipsoids with the same CODE. The default is crs.

--summary

When listing coordinate operations available between 2 CRS, return the result in a summary format, mentioning only the name of the coordinate operation, its accuracy and its area of use.

Note

only used for coordinate operation computation

-q

Turn on quiet mode. Quiet mode is only available for queries on single objects, and only one output format is selected. In that mode, only the PROJ, WKT or PROJJSON string is displayed, without other introduction output. The output is then potentially compatible of being piped in other utilities.

--area name_or_code

Specify an area of interest to restrict the results when researching coordinate operations between 2 CRS. The area of interest can be specified either as a name (e.g “Denmark - onshore”) or a AUTHORITY:CODE (EPSG:3237) This option is exclusive of --bbox.

Note

only used for coordinate operation computation

--bbox west_long,south_lat,east_long,north_lat

Specify an area of interest to restrict the results when researching coordinate operations between 2 CRS. The area of interest is specified as a bounding box with geographic coordinates, expressed in degrees in a unspecified geographic CRS. west_long and east_long should be in the [-180,180] range, and south_lat and north_lat in the [-90,90]. west_long is generally lower than east_long, except in the case where the area of interest crosses the antimeridian.

Note

only used for coordinate operation computation

--spatial-test contains|intersects

Specify how the area of use of coordinate operations found in the database are compared to the area of use specified explicitly with --area or --bbox, or derived implicitly from the area of use of the source and target CRS. By default, projinfo will only keep coordinate operations whose are of use is strictly within the area of interest (contains strategy). If using the intersects strategy, the spatial test is relaxed, and any coordinate operation whose area of use at least partly intersects the area of interest is listed.

Note

only used for coordinate operation computation

--crs-extent-use none|both|intersection|smallest

Specify which area of interest to consider when no explicit one is specified with --area or --bbox options. By default (smallest strategy), the area of use of the source or target CRS will be looked, and the one that is the smallest one in terms of area will be used as the area of interest. If using none, no area of interest is used. If using both, only coordinate operations that relate (contain or intersect depending of the --spatial-test strategy) to the area of use of both CRS are selected. If using intersection, the area of interest is the intersection of the bounding box of the area of use of the source and target CRS

Note

only used for coordinate operation computation

--grid-check none|discard_missing|sort

Specify how the presence or absence of a horizontal or vertical shift grid required for a coordinate operation affects the results returned when researching coordinate operations between 2 CRS. The default strategy is sort: in that case, all candidate operations are returned, but the actual availability of the grids is used to determine the sorting order. That is, if a coordinate operation involves using a grid that is not available in the PROJ resource directories (determined by the PROJ_LIB environment variable, it will be listed in the bottom of the results. The none strategy completely disables the checks of presence of grids and this returns the results as if all the grids where available. The discard_missing strategy discards results that involve grids not present in the PROJ resource directories.

Note

only used for coordinate operation computation

-show-superseded

When enabled, coordinate operations that are superseded by others will be listed. Note that supersession is not equivalent to deprecation: superseded operations are still considered valid although they have a better equivalent, whereas deprecated operations have been determined to be erroneous and are not considered at all.

Note

only used for coordinate operation computation

--pivot-crs always|if_no_direct_transformation|never|{auth:code[,auth:code]*}

Determine if intermediate (pivot) CRS can be used when researching coordinate operation between 2 CRS. A typical example is the WGS84 pivot. By default, projinfo will consider any potential pivot if there is no direct transformation ( if_no_direct_transformation). If using the never strategy, only direct transformations between the source and target CRS will be used. If using the always strategy, intermediate CRS will be considered even if there are direct transformations. It is also possible to restrict the pivot CRS to consider by specifying one or several CRS by their AUTHORITY:CODE.

Note

only used for coordinate operation computation

--boundcrs-to-wgs84

When specified, this option researches a coordinate operation from the base geographic CRS of the single CRS, source or target CRS to the WGS84 geographic CRS, and if found, wraps those CRS into a BoundCRS object. This is mostly to be used for early-binding approaches.

--main-db-path path

Specify the name and path of the database to be used by projinfo. The default is proj.db in the PROJ resource directories.

--aux-db-path path

Specify the name and path of auxiliary databases, that are to be combined with the main database. Those auxiliary databases must have a table structure that is identical to the main database, but can be partly filled and their entries can refer to entries of the main database. The option may be repeated to specify several auxiliary databases.

--identify

When used with an object definition, this queries the PROJ database to find known objects, typically CRS, that are close or identical to the object. Each candidate object is associated with an approximate likelihood percentage. This is useful when used with a WKT string that lacks a EPSG identifier, such as ESRI WKT1. This might also be used with PROJ strings. For example, +proj=utm +zone=31 +datum=WGS84 +type=crs will be identified with a likelihood of 70% to EPSG:32631

--c-ify

For developers only. Modify the string output of the utility so that it is easy to put those strings in C/C++ code

--single-line

Output WKT or PROJJSON strings on a single line, instead of multiple intended lines by default.

## Examples¶

1. Query the CRS object corresponding to EPSG:4326

projinfo EPSG:4326


Output:

PROJ.4 string:
+proj=longlat +datum=WGS84 +no_defs +type=crs

WKT2_2018 string:
GEOGCRS["WGS 84",
DATUM["World Geodetic System 1984",
ELLIPSOID["WGS 84",6378137,298.257223563,
LENGTHUNIT["metre",1]]],
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["unknown"],
AREA["World"],
BBOX[-90,-180,90,180]],
ID["EPSG",4326]]

1. List the coordinate operations between NAD27 (designed with its CRS name) and NAD83 (designed with its EPSG code 4269) within an area of interest

projinfo -s NAD27 -t EPSG:4269 --area "USA - Missouri"


Output:

DERIVED_FROM(EPSG):1241, NAD27 to NAD83 (1), 0.15 m, USA - CONUS including EEZ

PROJ string:
+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert \
+xy_in=deg +xy_out=rad +step +proj=hgridshift +grids=conus \
+step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1

WKT2_2018 string:
SOURCECRS[
DATUM["North American Datum 1927",
ELLIPSOID["Clarke 1866",6378206.4,294.978698213898,
LENGTHUNIT["metre",1]]],
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]]]],
TARGETCRS[
DATUM["North American Datum 1983",
ELLIPSOID["GRS 1980",6378137,298.257222101,
LENGTHUNIT["metre",1]]],
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]]]],
METHOD["CTABLE2"],
PARAMETERFILE["Latitude and longitude difference file","conus"],
OPERATIONACCURACY[0.15],
USAGE[
SCOPE["unknown"],
AREA["USA - CONUS including EEZ"],
BBOX[23.81,-129.17,49.38,-65.69]],
ID["DERIVED_FROM(EPSG)",1241]]

1. Export an object as a PROJJSON string

projinfo GDA94 -o PROJJSON -q


Output:

{
"type": "GeographicCRS",
"name": "GDA94",
"datum": {
"type": "GeodeticReferenceFrame",
"name": "Geocentric Datum of Australia 1994",
"ellipsoid": {
"name": "GRS 1980",
"semi_major_axis": 6378137,
"inverse_flattening": 298.257222101
}
},
"coordinate_system": {
"subtype": "ellipsoidal",
"axis": [
{
"name": "Geodetic latitude",
"abbreviation": "Lat",
"direction": "north",
"unit": "degree"
},
{
"name": "Geodetic longitude",
"abbreviation": "Lon",
"direction": "east",
"unit": "degree"
}
]
},
"area": "Australia - GDA",
"bbox": {
"south_latitude": -60.56,
"west_longitude": 93.41,
"north_latitude": -8.47,
"east_longitude": 173.35
},
"id": {
"authority": "EPSG",
"code": 4283
}
}