Proj

pyproj.Proj

class pyproj.proj.Proj(projparams=None, preserve_units=True, **kwargs)[source]

Bases: pyproj._proj.Proj

performs cartographic transformations (converts from longitude,latitude to native map projection x,y coordinates and vice versa) using proj (https://github.com/OSGeo/proj.4/wiki).

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 proj4 string (compatible with the proj command). See http://www.remotesensing.org/geotiff/proj_list 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.

__call__(*args, **kw)[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). 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)[source]

initialize a Proj class instance.

See the proj documentation (https://github.com/OSGeo/proj.4/wiki) for more information about projection parameters.

Parameters

  • projparams (int, str, dict, pyproj.CRS) – A proj.4 or WKT string, proj.4 dict, EPSG integer, or a pyproj.CRS instnace.

  • preserve_units (bool) – If false, will ensure +units=m.

  • **kwargs – proj.4 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()[source]

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()

Compares projections to see if they are exactly the same.

is_geocent()[source]
Returns

bool

Return type

True if projection in geocentric (x/y) coordinates

is_latlong()[source]
Returns

bool

Return type

True if projection in geographic (lon/lat) coordinates.

to_latlong()[source]

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

to_latlong_def()[source]

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