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.Proj(projparams=None, preserve_units=True, **kwargs)

Bases: pyproj._proj.Proj

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

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 https://proj.org/operations/projections/index.html for examples of key/value pairs defining different map projections.

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). If optional keyword ‘inverse’ is True (default is False), the inverse transformation from x/y to lon/lat is performed. If optional keyword ‘errcheck’ is True (default is False) an exception is raised if the transformation is invalid. If errcheck=False and the transformation is invalid, no exception is raised and 1.e30 is returned. If the optional keyword ‘preserve_units’ is True, the units in map projection coordinates are not forced to be meters.

Works with numpy and regular python array objects, python sequences and scalars.

srs

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

Type

str

crs

The CRS object associated with the Proj.

Type

CRS

proj_version

The major version number for PROJ.

Type

int

__call__(*args, **kw)

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). If optional keyword ‘inverse’ is True (default is False), the inverse transformation from x/y to lon/lat is performed. If optional keyword ‘errcheck’ is True (default is False) an exception is raised if the transformation is invalid. If errcheck=False and the transformation is invalid, no exception is raised and 1.e30 is returned.

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.

__init__(projparams=None, preserve_units=True, **kwargs)

initialize a Proj class instance.

See the PROJ documentation (https://proj.org) for more information about projection parameters.

Parameters

• projparams (int, str, dict, pyproj.CRS) – A PROJ or WKT string, PROJ dict, EPSG integer, or a pyproj.CRS instnace.

• 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) # use kwargs
>>> 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) # use proj4 string
>>> x,y = p2(-120.108, 34.36116666)
>>> 'x=%9.3f y=%11.3f' % (x,y)
'x=765975.641 y=3805993.134'
>>> p = Proj(init="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("+init=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(init="epsg:4214")
>>> x1, y1 = p1(116.366, 39.867)
>>> '{:.3f} {:.3f}'.format(x1, y1)
'2.031 0.696'
>>> x2, y2 = p1(x1, y1, inverse=True)
>>> '{:.3f} {:.3f}'.format(x2, y2)
'116.366 39.867'

definition_string()

Returns formal definition string for projection

>>> Proj('+init=epsg:4326').definition_string()
'proj=longlat datum=WGS84 no_defs ellps=WGS84 towgs84=0,0,0'
>>>

has_inverse

Returns true if this projection has an inverse

is_exact_same(self, other)

Compares Proj objects to see if they are exactly the same.

proj_version

object

Type

proj_version

to_latlong()

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

to_latlong_def()

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