Proj¶

pyproj.Proj is functionally equivalent to the proj command line tool in PROJ.

The PROJ docs say:

The `proj` program is limited to converting between geographic and
projection coordinates within one datum.

pyproj.Proj¶

class pyproj.Proj(projparams: Any | None = None, preserve_units: bool = True, **kwargs)[source]¶

Bases: Transformer

Performs cartographic transformations. Converts from longitude, latitude to native map projection x,y coordinates and vice versa using PROJ (https://proj.org).

srs¶

The string form of the user input used to create the Proj.

Type:: str

crs¶

The CRS object associated with the Proj.

Type:: pyproj.crs.CRS

__call__(longitude: Any, latitude: Any, inverse: bool = False, errcheck: bool = False, radians: bool = False) → tuple[Any, Any][source]¶

Calling a Proj class instance with the arguments lon, lat will convert lon/lat (in degrees) to x/y native map projection coordinates (in meters).

Inputs should be doubles (they will be cast to doubles if they are not, causing a slight performance hit).

Works with numpy and regular python array objects, python sequences and scalars, but is fastest for array objects.

Accepted numeric scalar or array:

Parameters:

longitude (scalar or array) – Input longitude coordinate(s).
latitude (scalar or array) – Input latitude coordinate(s).
inverse (bool, default=False) – If inverse is True the inverse transformation from x/y to lon/lat is performed.
radians (bool, default=False) – If True, will expect input data to be in radians and will return radians if the projection is geographic. Otherwise, it uses degrees. This does not work with pyproj 2 and is ignored. It will be enabled again in pyproj 3.
errcheck (bool, default=False) – If True, an exception is raised if the errors are found in the process. If False, inf is returned for errors.

Returns:

The transformed coordinates.

Return type:

tuple[Any, Any]

__init__(projparams: Any | None = None, preserve_units: bool = True, **kwargs) → None[source]¶

A Proj class instance is initialized with proj map projection control parameter key/value pairs. The key/value pairs can either be passed in a dictionary, or as keyword arguments, or as a PROJ string (compatible with the proj command). See Projections for examples of key/value pairs defining different map projections.

Parameters:

projparams (int, str, dict, pyproj.CRS) – A PROJ or WKT string, PROJ dict, EPSG integer, or a pyproj.CRS instance.
preserve_units (bool) – If false, will ensure +units=m.
**kwargs – PROJ projection parameters.

Example usage:

>>> from pyproj import Proj
>>> p = Proj(proj='utm',zone=10,ellps='WGS84', preserve_units=False)
>>> x,y = p(-120.108, 34.36116666)
>>> 'x=%9.3f y=%11.3f' % (x,y)
'x=765975.641 y=3805993.134'
>>> 'lon=%8.3f lat=%5.3f' % p(x,y,inverse=True)
'lon=-120.108 lat=34.361'
>>> # do 3 cities at a time in a tuple (Fresno, LA, SF)
>>> lons = (-119.72,-118.40,-122.38)
>>> lats = (36.77, 33.93, 37.62 )
>>> x,y = p(lons, lats)
>>> 'x: %9.3f %9.3f %9.3f' % x
'x: 792763.863 925321.537 554714.301'
>>> 'y: %9.3f %9.3f %9.3f' % y
'y: 4074377.617 3763936.941 4163835.303'
>>> lons, lats = p(x, y, inverse=True) # inverse transform
>>> 'lons: %8.3f %8.3f %8.3f' % lons
'lons: -119.720 -118.400 -122.380'
>>> 'lats: %8.3f %8.3f %8.3f' % lats
'lats:   36.770   33.930   37.620'
>>> p2 = Proj('+proj=utm +zone=10 +ellps=WGS84', preserve_units=False)
>>> x,y = p2(-120.108, 34.36116666)
>>> 'x=%9.3f y=%11.3f' % (x,y)
'x=765975.641 y=3805993.134'
>>> p = Proj("EPSG:32667", preserve_units=False)
>>> 'x=%12.3f y=%12.3f (meters)' % p(-114.057222, 51.045)
'x=-1783506.250 y= 6193827.033 (meters)'
>>> p = Proj("EPSG:32667")
>>> 'x=%12.3f y=%12.3f (feet)' % p(-114.057222, 51.045)
'x=-5851386.754 y=20320914.191 (feet)'
>>> # test data with radian inputs
>>> p1 = Proj("EPSG:4214")
>>> x1, y1 = p1(116.366, 39.867)
>>> f'{x1:.3f} {y1:.3f}'
'116.366 39.867'
>>> x2, y2 = p1(x1, y1, inverse=True)
>>> f'{x2:.3f} {y2:.3f}'
'116.366 39.867'

property accuracy: float¶

Expected accuracy of the transformation. -1 if unknown.

Type:: float

property area_of_use: AreaOfUse¶

Added in version 2.3.0.

Returns:: The area of use object with associated attributes.
Return type:: AreaOfUse

property definition: str¶

Definition of the projection.

Type:: str

definition_string() → str[source]¶

Returns formal definition string for projection

>>> Proj("EPSG:4326").definition_string()
'proj=longlat datum=WGS84 no_defs ellps=WGS84 towgs84=0,0,0'

property description: str¶

Description of the projection.

Type:: str

static from_crs(crs_from: Any, crs_to: Any, always_xy: bool = False, area_of_interest: AreaOfInterest | None = None, authority: str | None = None, accuracy: float | None = None, allow_ballpark: bool | None = None, force_over: bool = False, only_best: bool | None = None) → Transformer¶

Make a Transformer from a pyproj.crs.CRS or input used to create one.

See:

Added in version 2.2.0: always_xy

Added in version 2.3.0: area_of_interest

Added in version 3.1.0: authority, accuracy, allow_ballpark

Added in version 3.4.0: force_over

Added in version 3.5.0: only_best

Parameters:

crs_from (pyproj.crs.CRS or input used to create one) – Projection of input data.
crs_to (pyproj.crs.CRS or input used to create one) – Projection of output data.
always_xy (bool, default=False) – If true, the transform method will accept as input and return as output coordinates using the traditional GIS order, that is longitude, latitude for geographic CRS and easting, northing for most projected CRS.
area_of_interest (AreaOfInterest, optional) – The area of interest to help select the transformation.
authority (str, optional) – When not specified, coordinate operations from any authority will be searched, with the restrictions set in the authority_to_authority_preference database table related to the authority of the source/target CRS themselves. If authority is set to “any”, then coordinate operations from any authority will be searched. If authority is a non-empty string different from “any”, then coordinate operations will be searched only in that authority namespace (e.g. EPSG).
accuracy (float, optional) – The minimum desired accuracy (in metres) of the candidate coordinate operations.
allow_ballpark (bool, optional) – Set to False to disallow the use of Ballpark transformation in the candidate coordinate operations. Default is to allow.
force_over (bool, default=False) – If True, it will to force the +over flag on the transformation. Requires PROJ 9+.
only_best (bool, optional) – Can be set to True to cause PROJ to error out if the best transformation known to PROJ and usable by PROJ if all grids known and usable by PROJ were accessible, cannot be used. Best transformation should be understood as the transformation returned by proj_get_suggested_operation() if all known grids were accessible (either locally or through network). Note that the default value for this option can be also set with the PROJ_ONLY_BEST_DEFAULT environment variable, or with the only_best_default setting of proj.ini. The only_best kwarg overrides the default value if set. Requires PROJ 9.2+.

Return type:

Transformer

static from_pipeline(proj_pipeline: str) → Transformer¶

Make a Transformer from a PROJ pipeline string.

The pipeline operator

See:

Added in version 3.1.0: AUTH:CODE string support (e.g. EPSG:1671)

Allowed input:

a PROJ string
a WKT string
a PROJJSON string
an object code (e.g. “EPSG:1671” “urn:ogc:def:coordinateOperation:EPSG::1671”)
an object name. e.g “ITRF2014 to ETRF2014 (1)”. In that case as uniqueness is not guaranteed, heuristics are applied to determine the appropriate best match.
a OGC URN combining references for concatenated operations (e.g. “urn:ogc:def:coordinateOperation,coordinateOperation:EPSG::3895, coordinateOperation:EPSG::1618”)

Parameters:: proj_pipeline (str) – Projection pipeline string.
Return type:: Transformer

static from_proj(proj_from: Any, proj_to: Any, always_xy: bool = False, area_of_interest: AreaOfInterest | None = None) → Transformer¶

Make a Transformer from a pyproj.Proj or input used to create one.

Deprecated since version 3.4.1: from_crs() is preferred.

Added in version 2.2.0: always_xy

Added in version 2.3.0: area_of_interest

Parameters:

proj_from (pyproj.Proj or input used to create one) – Projection of input data.
proj_to (pyproj.Proj or input used to create one) – Projection of output data.
always_xy (bool, default=False) – If true, the transform method will accept as input and return as output coordinates using the traditional GIS order, that is longitude, latitude for geographic CRS and easting, northing for most projected CRS.
area_of_interest (AreaOfInterest, optional) – The area of interest to help select the transformation.

Return type:

Transformer

get_factors(longitude: Any, latitude: Any, radians: bool = False, errcheck: bool = False) → Factors[source]¶

Added in version 2.6.0.

Calculate various cartographic properties, such as scale factors, angular distortion and meridian convergence. Depending on the underlying projection values will be calculated either numerically (default) or analytically.

The function also calculates the partial derivatives of the given coordinate.

Accepted numeric scalar or array:

Parameters:

longitude (scalar or array) – Input longitude coordinate(s).
latitude (scalar or array) – Input latitude coordinate(s).
radians (bool, default=False) – If True, will expect input data to be in radians and will return radians if the projection is geographic. Otherwise, it uses degrees.
errcheck (bool, default=False) – If True, an exception is raised if the errors are found in the process. If False, inf is returned on error.

Return type:

Factors

get_last_used_operation() → Transformer¶

Added in version 3.4.0.

Note

Requires PROJ 9.1+

See: proj_trans_get_last_used_operation()

Returns:: The operation used in the transform call.
Return type:: Transformer

property has_inverse: bool¶

True if an inverse mapping exists.

Type:: bool

is_exact_same(other: Any) → bool¶

Check if the Transformer objects are the exact same. If it is not a Transformer, then it returns False.

Parameters:: other (Any)
Return type:: bool

property is_network_enabled: bool¶

Added in version 3.0.0.

Returns:: If the network is enabled.
Return type:: bool

itransform(points: Any, switch: bool = False, time_3rd: bool = False, radians: bool = False, errcheck: bool = False, direction: TransformDirection | str = TransformDirection.FORWARD) → Iterator[Iterable]¶

Iterator/generator version of the function pyproj.Transformer.transform.

See: proj_trans_generic()

Added in version 2.1.1: errcheck

Added in version 2.2.0: direction

Parameters:

points (list) – List of point tuples.
switch (bool, default=False) – If True x, y or lon,lat coordinates of points are switched to y, x or lat, lon. Default is False.
time_3rd (bool, default=False) – If the input coordinates are 3 dimensional and the 3rd dimension is time.
radians (bool, default=False) – If True, will expect input data to be in radians and will return radians if the projection is geographic. Otherwise, it uses degrees. Ignored for pipeline transformations with pyproj 2, but will work in pyproj 3.
errcheck (bool, default=False) – If True, an exception is raised if the errors are found in the process. If False, inf is returned for errors.
direction (pyproj.enums.TransformDirection, optional) – The direction of the transform. Default is pyproj.enums.TransformDirection.FORWARD.

Example

>>> from pyproj import Transformer
>>> transformer = Transformer.from_crs(4326, 2100)
>>> points = [(22.95, 40.63), (22.81, 40.53), (23.51, 40.86)]
>>> for pt in transformer.itransform(points): '{:.3f} {:.3f}'.format(*pt)
'2221638.801 2637034.372'
'2212924.125 2619851.898'
'2238294.779 2703763.736'
>>> pipeline_str = (
...     "+proj=pipeline +step +proj=longlat +ellps=WGS84 "
...     "+step +proj=unitconvert +xy_in=rad +xy_out=deg"
... )
>>> pipe_trans = Transformer.from_pipeline(pipeline_str)
>>> for pt in pipe_trans.itransform([(2.1, 0.001)]):
...     '{:.3f} {:.3f}'.format(*pt)
'2.100 0.001'
>>> transproj = Transformer.from_crs(
...     {"proj":'geocent', "ellps":'WGS84', "datum":'WGS84'},
...     "EPSG:4326",
...     always_xy=True,
... )
>>> for pt in transproj.itransform(
...     [(-2704026.010, -4253051.810, 3895878.820)],
...     radians=True,
... ):
...     '{:.3f} {:.3f} {:.3f}'.format(*pt)
'-2.137 0.661 -20.531'
>>> transprojr = Transformer.from_crs(
...     "EPSG:4326",
...     {"proj":'geocent', "ellps":'WGS84', "datum":'WGS84'},
...     always_xy=True,
... )
>>> for pt in transprojr.itransform(
...     [(-2.137, 0.661, -20.531)],
...     radians=True
... ):
...     '{:.3f} {:.3f} {:.3f}'.format(*pt)
'-2704214.394 -4254414.478 3894270.731'
>>> transproj_eq = Transformer.from_crs(
...     'EPSG:4326',
...     '+proj=longlat +datum=WGS84 +no_defs +type=crs',
...     always_xy=True,
... )
>>> for pt in transproj_eq.itransform([(-2.137, 0.661)]):
...     '{:.3f} {:.3f}'.format(*pt)
'-2.137 0.661'

property name: str¶

Name of the projection.

Type:: str

property operations: tuple[CoordinateOperation] | None¶

Added in version 2.4.0.

Returns:: The operations in a concatenated operation.
Return type:: tuple[CoordinateOperation]

property remarks: str¶

Added in version 2.4.0.

Returns:: Remarks about object.
Return type:: str

property scope: str¶

Added in version 2.4.0.

Returns:: Scope of object.
Return type:: str

property source_crs: CRS | None¶

Added in version 3.3.0.

Returns:: The source CRS of a CoordinateOperation.
Return type:: CRS | None

property target_crs: CRS | None¶

Added in version 3.3.0.

Returns:: The target CRS of a CoordinateOperation.
Return type:: CRS | None

to_json(pretty: bool = False, indentation: int = 2) → str¶

Convert the projection to a JSON string.

Added in version 2.4.0.

Parameters:

pretty (bool, default=False) – If True, it will set the output to be a multiline string.
indentation (int, default=2) – If pretty is True, it will set the width of the indentation.

Returns:

The JSON string.

Return type:

str

to_json_dict() → dict¶

Convert the projection to a JSON dictionary.

Added in version 2.4.0.

Returns:: The JSON dictionary.
Return type:: dict

to_latlong() → Proj[source]¶: return a new Proj instance which is the geographic (lat/lon) coordinate version of the current projection

to_latlong_def() → str | None[source]¶: return the definition string of the geographic (lat/lon) coordinate version of the current projection

to_proj4(version: ProjVersion | str = ProjVersion.PROJ_5, pretty: bool = False) → str¶

Convert the projection to a PROJ string.

Added in version 3.1.0.

Parameters:

version (pyproj.enums.ProjVersion) – The version of the PROJ string output. Default is pyproj.enums.ProjVersion.PROJ_5.
pretty (bool, default=False) – If True, it will set the output to be a multiline string.

Returns:

The PROJ string.

Return type:

str

to_wkt(version: WktVersion | str = WktVersion.WKT2_2019, pretty: bool = False) → str¶

Convert the projection to a WKT string.

Version options:

WKT2_2015
WKT2_2015_SIMPLIFIED
WKT2_2019
WKT2_2019_SIMPLIFIED
WKT1_GDAL
WKT1_ESRI

Parameters:

version (pyproj.enums.WktVersion, optional) – The version of the WKT output. Default is pyproj.enums.WktVersion.WKT2_2019.
pretty (bool, default=False) – If True, it will set the output to be a multiline string.

Returns:

The WKT string.

Return type:

str

transform(xx, yy, zz=None, tt=None, radians=False, errcheck=False, direction=TransformDirection.FORWARD, inplace=False)¶

Transform points between two coordinate systems.

See: proj_trans_generic()

Added in version 2.1.1: errcheck

Added in version 2.2.0: direction

Added in version 3.2.0: inplace

Accepted numeric scalar or array:

Parameters:

xx (scalar or array) – Input x coordinate(s).
yy (scalar or array) – Input y coordinate(s).
zz (scalar or array, optional) – Input z coordinate(s).
tt (scalar or array, optional) – Input time coordinate(s).
radians (bool, default=False) – If True, will expect input data to be in radians and will return radians if the projection is geographic. Otherwise, it uses degrees. Ignored for pipeline transformations with pyproj 2, but will work in pyproj 3.
errcheck (bool, default=False) – If True, an exception is raised if the errors are found in the process. If False, inf is returned for errors.
direction (pyproj.enums.TransformDirection, optional) – The direction of the transform. Default is pyproj.enums.TransformDirection.FORWARD.
inplace (bool, default=False) – If True, will attempt to write the results to the input array instead of returning a new array. This will fail if the input is not an array in C order with the double data type.

Example

>>> from pyproj import Transformer
>>> transformer = Transformer.from_crs("EPSG:4326", "EPSG:3857")
>>> x3, y3 = transformer.transform(33, 98)
>>> f"{x3:.3f}  {y3:.3f}"
'10909310.098  3895303.963'
>>> pipeline_str = (
...     "+proj=pipeline +step +proj=longlat +ellps=WGS84 "
...     "+step +proj=unitconvert +xy_in=rad +xy_out=deg"
... )
>>> pipe_trans = Transformer.from_pipeline(pipeline_str)
>>> xt, yt = pipe_trans.transform(2.1, 0.001)
>>> f"{xt:.3f}  {yt:.3f}"
'2.100  0.001'
>>> transproj = Transformer.from_crs(
...     {"proj":'geocent', "ellps":'WGS84', "datum":'WGS84'},
...     "EPSG:4326",
...     always_xy=True,
... )
>>> xpj, ypj, zpj = transproj.transform(
...     -2704026.010,
...     -4253051.810,
...     3895878.820,
...     radians=True,
... )
>>> f"{xpj:.3f} {ypj:.3f} {zpj:.3f}"
'-2.137 0.661 -20.531'
>>> transprojr = Transformer.from_crs(
...     "EPSG:4326",
...     {"proj":'geocent', "ellps":'WGS84', "datum":'WGS84'},
...     always_xy=True,
... )
>>> xpjr, ypjr, zpjr = transprojr.transform(xpj, ypj, zpj, radians=True)
>>> f"{xpjr:.3f} {ypjr:.3f} {zpjr:.3f}"
'-2704026.010 -4253051.810 3895878.820'
>>> transformer = Transformer.from_crs("EPSG:4326", 4326)
>>> xeq, yeq = transformer.transform(33, 98)
>>> f"{xeq:.0f}  {yeq:.0f}"
'33  98'

transform_bounds(left: float, bottom: float, right: float, top: float, densify_pts: int = 21, radians: bool = False, errcheck: bool = False, direction: TransformDirection | str = TransformDirection.FORWARD) → tuple[float, float, float, float]¶

Added in version 3.1.0.

See: proj_trans_bounds()

Transform boundary densifying the edges to account for nonlinear transformations along these edges and extracting the outermost bounds.

If the destination CRS is geographic and right < left then the bounds crossed the antimeridian. In this scenario there are two polygons, one on each side of the antimeridian. The first polygon should be constructed with (left, bottom, 180, top) and the second with (-180, bottom, top, right).

To construct the bounding polygons with shapely:

def bounding_polygon(left, bottom, right, top):
    if right < left:
        return shapely.geometry.MultiPolygon(
            [
                shapely.geometry.box(left, bottom, 180, top),
                shapely.geometry.box(-180, bottom, right, top),
            ]
        )
    return shapely.geometry.box(left, bottom, right, top)

Parameters:

left (float) – Minimum bounding coordinate of the first axis in source CRS (or the target CRS if using the reverse direction).
bottom (float) – Minimum bounding coordinate of the second axis in source CRS. (or the target CRS if using the reverse direction).
right (float) – Maximum bounding coordinate of the first axis in source CRS. (or the target CRS if using the reverse direction).
top (float) – Maximum bounding coordinate of the second axis in source CRS. (or the target CRS if using the reverse direction).
densify_points (uint, default=21) – Number of points to add to each edge to account for nonlinear edges produced by the transform process. Large numbers will produce worse performance.
radians (bool, default=False) – If True, will expect input data to be in radians and will return radians if the projection is geographic. Otherwise, it uses degrees.
errcheck (bool, default=False) – If True, an exception is raised if the errors are found in the process. If False, inf is returned for errors.
direction (pyproj.enums.TransformDirection, optional) – The direction of the transform. Default is pyproj.enums.TransformDirection.FORWARD.

Returns:

left, bottom, right, top – Outermost coordinates in target coordinate reference system.

Return type:

float

pyproj.proj.Factors¶

class pyproj.proj.Factors(meridional_scale, parallel_scale, areal_scale, angular_distortion, meridian_parallel_angle, meridian_convergence, tissot_semimajor, tissot_semiminor, dx_dlam, dx_dphi, dy_dlam, dy_dphi)¶

Added in version 2.6.0.

These are the scaling and angular distortion factors.

See PROJ PJ_FACTORS documentation.

Parameters:

meridional_scale (list[float]) – Meridional scale at coordinate.
parallel_scale (list[float]) – Parallel scale at coordinate.
areal_scale (list[float]) – Areal scale factor at coordinate.
angular_distortion (list[float]) – Angular distortion at coordinate.
meridian_parallel_angle (list[float]) – Meridian/parallel angle at coordinate.
meridian_convergence (list[float]) – Meridian convergence at coordinate. Sometimes also described as grid declination.
tissot_semimajor (list[float]) – Maximum scale factor.
tissot_semiminor (list[float]) – Minimum scale factor.
dx_dlam (list[float]) – Partial derivative of coordinate.
dx_dphi (list[float]) – Partial derivative of coordinate.
dy_dlam (list[float]) – Partial derivative of coordinate.
dy_dphi (list[float]) – Partial derivative of coordinate.

angular_distortion¶: Alias for field number 3

areal_scale¶: Alias for field number 2

dx_dlam¶: Alias for field number 8

dx_dphi¶: Alias for field number 9

dy_dlam¶: Alias for field number 10

dy_dphi¶: Alias for field number 11

meridian_convergence¶: Alias for field number 5

meridian_parallel_angle¶: Alias for field number 4

meridional_scale¶: Alias for field number 0

parallel_scale¶: Alias for field number 1

tissot_semimajor¶: Alias for field number 6

tissot_semiminor¶: Alias for field number 7