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: Optional[Any] = None, preserve_units: bool = True, **kwargs)[source]

Bases: pyproj.transformer.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.

Parameters

  • longitude (scalar or array (numpy or python)) – Input longitude coordinate(s).

  • latitude (scalar or array (numpy or python)) – 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: Optional[Any] = 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: pyproj.aoi.AreaOfUse

New 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, skip_equivalent: bool = False, always_xy: bool = False, area_of_interest: Optional[pyproj.aoi.AreaOfInterest] = None, authority: Optional[str] = None, accuracy: Optional[float] = None, allow_ballpark: Optional[bool] = None) → pyproj.transformer.Transformer

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

New in version 2.1.2: skip_equivalent

New in version 2.2.0: always_xy

New in version 2.3.0: area_of_interest

New in version 3.1.0: authority, accuracy, allow_ballpark

Deprecated since version 3.1: skip_equivalent

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.

  • skip_equivalent (bool, default=False) – DEPRECATED: If true, will skip the transformation operation if input and output projections are equivalent.

  • 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 (pyproj.transformer.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.

Return type

Transformer

static from_pipeline(proj_pipeline: str) → pyproj.transformer.Transformer

Make a Transformer from a PROJ pipeline string.

The pipeline operator

New in version 3.1.0: AUTH:CODE string suppor (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, skip_equivalent: bool = False, always_xy: bool = False, area_of_interest: Optional[pyproj.aoi.AreaOfInterest] = None) → pyproj.transformer.Transformer

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

New in version 2.1.2: skip_equivalent

New in version 2.2.0: always_xy

New in version 2.3.0: area_of_interest

Deprecated since version 3.1: skip_equivalent

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.

  • skip_equivalent (bool, default=False) – DEPRECATED: If true, will skip the transformation operation if input and output projections are equivalent.

  • 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 (pyproj.transformer.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) → importlib._bootstrap.Factors[source]

New 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.

Parameters

  • longitude (scalar or array (numpy or python)) – Input longitude coordinate(s).

  • latitude (scalar or array (numpy or python)) – 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

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

New in version 3.0.0.

bool:

If the network is enabled.

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

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

New in version 2.1.1: errcheck

New 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_proj(
...     '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: Optional[Tuple[pyproj._crs.CoordinateOperation]]

New in version 2.4.0.

Returns

The operations in a concatenated operation.

Return type

Tuple[CoordinateOperation]

property remarks: str

New in version 2.4.0.

Returns

Remarks about object.

Return type

str

property scope: str

New in version 2.4.0.

Returns

Scope of object.

Return type

str

property source_crs: Optional[pyproj.crs.crs.CRS]

New in version 3.3.0.

Returns

The source CRS of a CoordinateOperation.

Return type

Optional[CRS]

property target_crs: Optional[pyproj.crs.crs.CRS]

New in version 3.3.0.

Returns

The target CRS of a CoordinateOperation.

Return type

Optional[CRS]

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

Convert the projection to a JSON string.

New 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.

New in version 2.4.0.

Returns

The JSON dictionary.

Return type

dict

to_latlong() → pyproj.proj.Proj[source]

return a new Proj instance which is the geographic (lat/lon) coordinate version of the current projection

to_latlong_def() → Optional[str][source]

return the definition string of the geographic (lat/lon) coordinate version of the current projection

to_proj4(version: Union[pyproj.enums.ProjVersion, str] = ProjVersion.PROJ_5, pretty: bool = False) → str

Convert the projection to a PROJ string.

New in version 3.1.0.

Parameters
Returns

The PROJ string.

Return type

str

to_wkt(version: Union[pyproj.enums.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
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.

New in version 2.1.1: errcheck

New in version 2.2.0: direction

New in version 3.2.0: inplace

Parameters

  • xx (scalar or array (numpy or python)) – Input x coordinate(s).

  • yy (scalar or array (numpy or python)) – Input y coordinate(s).

  • zz (scalar or array (numpy or python), optional) – Input z coordinate(s).

  • tt (scalar or array (numpy or python), 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_proj("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: Union[pyproj.enums.TransformDirection, str] = TransformDirection.FORWARD) → Tuple[float, float, float, float]

New in version 3.1.0.

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)

New 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