Package pyproj

points2 = transform(p1, p2, points1, radians=False) Iterator/generator version of the function pyproj.transform. Transform points between two coordinate systems defined by the Proj instances p1 and p2. This function can be used as an alternative to pyproj.transform when there is a need to transform a big number of coordinates lazily, for example when reading and processing from a file. Points1 is an iterable/generator of coordinates x1,y1(,z1) or lon1,lat1(,z1) in the coordinate system defined by p1. Points2 is an iterator that returns tuples of x2,y2(,z2) or lon2,lat2(,z2) coordinates in the coordinate system defined by p2. z are provided optionally.

Points1 can be:

• a tuple/list of tuples/lists i.e. for 2d points: [(xi,yi),(xj,yj),....(xn,yn)]
• a Nx3 or Nx2 2d numpy array where N is the point number
• a generator of coordinates (xi,yi) for 2d points or (xi,yi,zi) for 3d

If optional keyword 'switch' is True (default is False) then x, y or lon,lat coordinates of points are switched to y, x or lat, lon. If optional keyword 'radians' is True (default is False) and p1 is defined in geographic coordinate (pj.is_latlong() is True), x1,y1 is interpreted as radians instead of the default degrees. Similarly, if p2 is defined in geographic coordinates and radians=True, x2, y2 are returned in radians instead of degrees. if p1.is_latlong() and p2.is_latlong() both are False, the radians keyword has no effect. Example usage: >>> # projection 1: WGS84 >>> # (defined by epsg code 4326) >>> p1 = Proj(init='epsg:4326') >>> # projection 2: GGRS87 / Greek Grid >>> p2 = Proj(init='epsg:2100') >>> # Three points with coordinates lon, lat in p1 >>> points = [(22.95, 40.63), (22.81, 40.53), (23.51, 40.86)] >>> # transform this point to projection 2 coordinates. >>> for pt in itransform(p1,p2,points): '%6.3f %7.3f' % pt '411050.470 4497928.574' '399060.236 4486978.710' '458553.243 4523045.485'

x2, y2, z2 = transform(p1, p2, x1, y1, z1, radians=False)

Transform points between two coordinate systems defined by the Proj instances p1 and p2.

The points x1,y1,z1 in the coordinate system defined by p1 are transformed to x2,y2,z2 in the coordinate system defined by p2.

z1 is optional, if it is not set it is assumed to be zero (and only x2 and y2 are returned).

In addition to converting between cartographic and geographic projection coordinates, this function can take care of datum shifts (which cannot be done using the __call__ method of the Proj instances). It also allows for one of the coordinate systems to be geographic (proj = 'latlong').

If optional keyword 'radians' is True (default is False) and p1 is defined in geographic coordinate (pj.is_latlong() is True), x1,y1 is interpreted as radians instead of the default degrees. Similarly, if p2 is defined in geographic coordinates and radians=True, x2, y2 are returned in radians instead of degrees. if p1.is_latlong() and p2.is_latlong() both are False, the radians keyword has no effect.

x,y and z can be numpy or regular python arrays, python lists/tuples or scalars. Arrays are fastest. For projections in geocentric coordinates, values of x and y are given in meters. z is always meters.

Example usage:

>>> # projection 1: UTM zone 15, grs80 ellipse, NAD83 datum
>>> # (defined by epsg code 26915)
>>> p1 = Proj(init='epsg:26915')
>>> # projection 2: UTM zone 15, clrk66 ellipse, NAD27 datum
>>> p2 = Proj(init='epsg:26715')
>>> # find x,y of Jefferson City, MO.
>>> x1, y1 = p1(-92.199881,38.56694)
>>> # transform this point to projection 2 coordinates.
>>> x2, y2 = transform(p1,p2,x1,y1)
>>> '%9.3f %11.3f' % (x1,y1)
'569704.566 4269024.671'
>>> '%9.3f %11.3f' % (x2,y2)
'569722.342 4268814.027'
>>> '%8.3f %5.3f' % p2(x2,y2,inverse=True)
' -92.200 38.567'
>>> # process 3 points at a time in a tuple
>>> lats = (38.83,39.32,38.75) # Columbia, KC and StL Missouri
>>> lons = (-92.22,-94.72,-90.37)
>>> x1, y1 = p1(lons,lats)
>>> x2, y2 = transform(p1,p2,x1,y1)
>>> xy = x1+y1
>>> '%9.3f %9.3f %9.3f %11.3f %11.3f %11.3f' % xy
'567703.344 351730.944 728553.093 4298200.739 4353698.725 4292319.005'
>>> xy = x2+y2
>>> '%9.3f %9.3f %9.3f %11.3f %11.3f %11.3f' % xy
'567721.149 351747.558 728569.133 4297989.112 4353489.644 4292106.305'
>>> lons, lats = p2(x2,y2,inverse=True)
>>> xy = lons+lats
>>> '%8.3f %8.3f %8.3f %5.3f %5.3f %5.3f' % xy
' -92.220  -94.720  -90.370 38.830 39.320 38.750'
>>> # test datum shifting, installation of extra datum grid files.
>>> p1 = Proj(proj='latlong',datum='WGS84')
>>> x1 = -111.5; y1 = 45.25919444444
>>> p2 = Proj(proj="utm",zone=10,datum='NAD27')
>>> x2, y2 = transform(p1, p2, x1, y1)
>>> "%s  %s" % (str(x2)[:9],str(y2)[:9])
'1402285.9  5076292.4'

pj_ellps

Value:

{'APL4.9': {'a': 6378137.0, 'description': 'Appl. Physics. 1965', 'rf': 298.25}, 'CPM': {'a': 6375738.7, 'description': 'Comm. des Poids et Mesures 1799', 'rf': 334.29}, 'GRS67': {'a': 6378160.0, 'description': 'GRS 67(IUGG 1967)', ...

pj_list

Value:

{'aea': 'Albers Equal Area', 'aeqd': 'Azimuthal Equidistant', 'airy': 'Airy', 'aitoff': 'Aitoff', 'alsk': 'Mod. Stererographics of Alaska', 'apian': 'Apian Globular I', 'august': 'August Epicycloidal', 'bacon': 'Bacon Globular', ...