projinfo(1) PROJ projinfo(1)
NAME
projinfo - Geodetic object and coordinate operation queries
SYNOPSIS
projinfo
[-o formats] [-k crs|operation|datum|ensemble|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]
[--grid-check none|discard_missing|sort|known_available]
[--pivot-crs always|if_no_direct_transformation|never|{auth:code[,auth:code]*}]
[--show-superseded] [--hide-ballpark] [--accuracy {accuracy}]
[--allow-ellipsoidal-height-as-vertical-crs]
[--boundcrs-to-wgs84]
[--authority name]
[--main-db-path path] [--aux-db-path path]*
[--dump-db-structure]
[--identify] [--3d]
[--output-id AUTH:CODE]
[--c-ify] [--single-line]
--searchpaths | --remote-data |
--list-crs [list-crs-filter] |
--dump-db-structure [{object_definition} | {object_reference}] |
{object_definition} | {object_reference} |
(-s {srs_def} [--s_epoch {epoch}] -t {srs_def} [--t_epoch {epoch}]) |
({srs_def} {srs_def})
where {object_definition} or {srs_def} is one of the possibilities
accepted by proj_create()
o a proj-string,
o a WKT string,
o an object code (like "EPSG:4326", "urn:ogc:def:crs:EPSG::4326",
"urn:ogc:def:coordinateOperation:EPSG::1671"),
o an Object name. e.g "WGS 84", "WGS 84 / UTM zone 31N". In that
case as uniqueness is not guaranteed, heuristics are applied to
determine the appropriate best match.
o a CRS name and a coordinate epoch, separated with '@'. For example
"ITRF2014@2025.0". (added in 9.2)
o a OGC URN combining references for compound coordinate reference
systems (e.g "urn:ogc:def:crs,crs:EPSG::2393,crs:EPSG::5717" or
custom abbreviated syntax "EPSG:2393+5717"),
o a OGC URN combining references for references for projected or
derived CRSs e.g. for Projected 3D CRS "UTM zone 31N / WGS 84
(3D)":
"urn:ogc:def:crs,crs:EPSG::4979,cs:PROJ::ENh,coordinateOperation:EPSG::16031"
(added in 6.2)
o Extension of OGC URN for CoordinateMetadata. e.g.
"urn:ogc:def:CoordinateMetadata:NRCAN::NAD83_CSRS_1997_MTM11_HT2_1997"
o a OGC URN combining references for concatenated operations (e.g.
"urn:ogc:def:coordinateOperation,coordinateOperation:EPSG::3895,coordinateOperation:EPSG::1618")
o a PROJJSON string. The jsonschema is at
https://proj.org/schemas/v0.4/projjson.schema.json (added in 6.2)
o a compound CRS made from two object names separated with " + ".
e.g. "WGS 84 + EGM96 height" (added in 7.1)
{object_reference} is a filename preceded by the '@' character. The
file referenced by the {object_reference} must contain a valid
{object_definition}.
The usage of "{srs_def} {srs_def}" is equivalent to "-s {srs_def} -t
{srs_def}" (added in 9.5).
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
utility 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, WKT2:2019, WKT1:GDAL, WKT1:ESRI, PROJJSON,
SQL.
Except all and default, other formats can be preceded by - to
disable them.
NOTE:
WKT2_2019 was previously called WKT2_2018.
NOTE:
Before PROJ 6.3.0, WKT1:GDAL was implicitly calling
--boundcrs-to-wgs84. This is no longer the case.
NOTE:
When SQL is specified, --output-id must be specified.
-k crs|operation|datum|ensemble|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|known_available
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 (if PROJ_NETWORK is not
defined). 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_DATA 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. The
known_available strategy discards results that involve grids not
present in the PROJ resource directories and that are not known
of the CDN. This is the default strategy is PROJ_NETWORK is set
to ON.
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
--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
--hide-ballpark
Added in version 7.1.
Hides any coordinate operation that is, or contains, a Ballpark
transformation
NOTE:
only used for coordinate operation computation
--accuracy {accuracy}
Added in version 8.0.
Sets the minimum desired accuracy for returned coordinate
operations.
NOTE:
only used for coordinate operation computation
--allow-ellipsoidal-height-as-vertical-crs
Added in version 8.0.
Allows exporting a geographic or projected 3D CRS as a compound
CRS whose vertical CRS represents the ellipsoidal height.
NOTE:
only used for CRS, and with WKT1:GDAL output format
--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.
--authority name
Specify the name of the authority into which to restrict looks
up for objects, when specifying an object by name or when
coordinate operations are computed. The default is to allow all
authorities.
When used with SQL output, this restricts the authorities to
which intermediate objects can belong to (the default is EPSG
and PROJ). Note that the authority of the --output-id option
will also be implicitly added.
--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
--dump-db-structure
Added in version 8.1.
Outputs the sequence of SQL statements to create a new empty
valid auxiliary database. This option can be specified as the
only switch of the utility. If also specifying a CRS object and
the --output-id option, the definition of the object as SQL
statements will be appended.
--list-crs [list-crs-filter]
Added in version 8.1.
Outputs a list (authority name:code and CRS name) of the
filtered CRSs from the database. If no filter is provided all
authority names and types of non deprecated CRSs are dumped.
list-crs-filter is a comma separated combination of:
allow_deprecated,geodetic,geocentric,
geographic,geographic_2d,geographic_3d,vertical,projected,compound.
Affected by options --authority, --area, --bbox and
--spatial-test
A visual alternative is the webpage CRS Explorer .
--3d Added in version 6.3.
"Promote" 2D CRS(s) to their 3D version, where the vertical axis
is the ellipsoidal height in metres, using the ellipsoid of the
base geodetic CRS. Depending on PROJ versions and the exact
nature of the CRS involved, especially before PROJ 9.1, a mix of
2D and 3D CRS could lead to 2D or 3D transformations. Starting
with PROJ 9.1, both CRS need to be 3D for vertical
transformation to possibly happen.
--output-id=AUTH:NAME
Added in version 8.1.
Identifier to assign to the object (for SQL output).
It is strongly recommended that new objects should not be added
in common registries, such as EPSG, ESRI, IAU, etc. Users
should use a custom authority name instead. If a new object
should be added to the official EPSG registry, users are invited
to follow the procedure explained at
https://epsg.org/dataset-change-requests.html.
Combined with --dump-db-structure, users can create auxiliary
databases, instead of directly modifying the main proj.db
database. See the example how to export to an auxiliary
database.
Those auxiliary databases can be specified through
proj_context_set_database_path() or the PROJ_AUX_DB environment
variable.
--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 PROJ, WKT or PROJJSON strings on a single line, instead
of multiple indented lines by default.
--searchpaths
Added in version 7.0.
Output the directories into which PROJ resources will be looked
for (if not using C API such as proj_context_set_search_paths()
that will override them.
--remote-data
Added in version 7.0.
Display information regarding if Network capabilities is
enabled, and the related URL.
--s_epoch
Added in version 9.4.
Epoch of coordinates in the source CRS, as decimal year. Only
applies to a dynamic CRS.
--t_epoch
Added in version 9.4.
Epoch of coordinates in the target CRS, as decimal year. Only
applies to a dynamic CRS.
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
WKT2:2019 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]]
2. 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
WKT2:2019 string:
COORDINATEOPERATION["NAD27 to NAD83 (1)",
SOURCECRS[
GEOGCRS["NAD27",
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[
GEOGCRS["NAD83",
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]]
3. 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
}
}
4. Exporting the SQL statements to insert a new CRS in an auxiliary
database.
# Get the SQL statements for a custom CRS
projinfo "+proj=merc +lat_ts=5 +datum=WGS84 +type=crs +title=my_crs" --output-id HOBU:MY_CRS -o SQL -q > my_crs.sql
cat my_crs.sql
# Initialize an auxiliary database with the schema of the reference database
echo ".schema" | sqlite3 /path/to/proj.db | sqlite3 aux.db
# Append the content of the definition of HOBU:MY_CRS
sqlite3 aux.db < my_crs.db
# Check that everything works OK
projinfo --aux-db-path aux.db HOBU:MY_CRS
or more simply:
# Create an auxiliary database with the definition of a custom CRS.
projinfo "+proj=merc +lat_ts=5 +datum=WGS84 +type=crs +title=my_crs" --output-id HOBU:MY_CRS --dump-db-structure | sqlite3 aux.db
# Check that everything works OK
projinfo --aux-db-path aux.db HOBU:MY_CRS
Output:
INSERT INTO geodetic_crs VALUES('HOBU','GEODETIC_CRS_MY_CRS','unknown','','geographic 2D','EPSG','6424','EPSG','6326',NULL,0);
INSERT INTO usage VALUES('HOBU','USAGE_GEODETIC_CRS_MY_CRS','geodetic_crs','HOBU','GEODETIC_CRS_MY_CRS','PROJ','EXTENT_UNKNOWN','PROJ','SCOPE_UNKNOWN');
INSERT INTO conversion VALUES('HOBU','CONVERSION_MY_CRS','unknown','','EPSG','9805','Mercator (variant B)','EPSG','8823','Latitude of 1st standard parallel',5,'EPSG','9122','EPSG','8802','Longitude of natural origin',0,'EPSG','9122','EPSG','8806','False easting',0,'EPSG','9001','EPSG','8807','False northing',0,'EPSG','9001',NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL,0);
INSERT INTO usage VALUES('HOBU','USAGE_CONVERSION_MY_CRS','conversion','HOBU','CONVERSION_MY_CRS','PROJ','EXTENT_UNKNOWN','PROJ','SCOPE_UNKNOWN');
INSERT INTO projected_crs VALUES('HOBU','MY_CRS','my_crs','','EPSG','4400','HOBU','GEODETIC_CRS_MY_CRS','HOBU','CONVERSION_MY_CRS',NULL,0);
INSERT INTO usage VALUES('HOBU','USAGE_PROJECTED_CRS_MY_CRS','projected_crs','HOBU','MY_CRS','PROJ','EXTENT_UNKNOWN','PROJ','SCOPE_UNKNOWN');
PROJ.4 string:
+proj=merc +lat_ts=5 +lon_0=0 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs +type=crs
WKT2:2019 string:
PROJCRS["my_crs",
BASEGEOGCRS["unknown",
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)"],
ELLIPSOID["WGS 84",6378137,298.257223563,
LENGTHUNIT["metre",1]],
ENSEMBLEACCURACY[2.0]],
PRIMEM["Greenwich",0,
ANGLEUNIT["degree",0.0174532925199433]],
ID["HOBU","GEODETIC_CRS_MY_CRS"]],
CONVERSION["unknown",
METHOD["Mercator (variant B)",
ID["EPSG",9805]],
PARAMETER["Latitude of 1st standard parallel",5,
ANGLEUNIT["degree",0.0174532925199433],
ID["EPSG",8823]],
PARAMETER["Longitude of natural origin",0,
ANGLEUNIT["degree",0.0174532925199433],
ID["EPSG",8802]],
PARAMETER["False easting",0,
LENGTHUNIT["metre",1],
ID["EPSG",8806]],
PARAMETER["False northing",0,
LENGTHUNIT["metre",1],
ID["EPSG",8807]]],
CS[Cartesian,2],
AXIS["(E)",east,
ORDER[1],
LENGTHUNIT["metre",1]],
AXIS["(N)",north,
ORDER[2],
LENGTHUNIT["metre",1]],
ID["HOBU","MY_CRS"]]
5. Get the WKT representation of EPSG:25832 in the WKT1:GDAL output
format and on a single line
projinfo -o WKT1:GDAL --single-line EPSG:25832
Output:
WKT1:GDAL string:
PROJCS["ETRS89 / UTM zone 32N",GEOGCS["ETRS89",DATUM["European_Terrestrial_Reference_System_1989",SPHEROID["GRS 1980",6378137,298.257222101,AUTHORITY["EPSG","7019"]],AUTHORITY["EPSG","6258"]],PRIMEM["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT["degree",0.0174532925199433,AUTHORITY["EPSG","9122"]],AUTHORITY["EPSG","4258"]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",9],PARAMETER["scale_factor",0.9996],PARAMETER["false_easting",500000],PARAMETER["false_northing",0],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Easting",EAST],AXIS["Northing",NORTH],AUTHORITY["EPSG","25832"]]
SEE ALSO
cs2cs(1), cct(1), geod(1), gie(1), proj(1), projsync(1)
BUGS
A list of known bugs can be found at
https://github.com/OSGeo/PROJ/issues where new bug reports can be
submitted to.
HOME PAGE
https://proj.org/
AUTHOR
Even Rouault
COPYRIGHT
1983-2025, PROJ contributors
9.6 08 Sep 2025 projinfo(1)
proj 9.7.0 - Generated Thu Oct 16 18:17:47 CDT 2025