""" Pyrex wrapper to provide python interfaces to PROJ.4 (http://proj.maptools.org) functions. Performs cartographic transformations and geodetic computations. The Proj class can convert from geographic (longitude,latitude) to native map projection (x,y) coordinates and vice versa, or from one map projection coordinate system directly to another. The Geod class can perform forward and inverse geodetic, or Great Circle, computations. The forward computation involves determining latitude, longitude and back azimuth of a terminus point given the latitude and longitude of an initial point, plus azimuth and distance. The inverse computation involves determining the forward and back azimuths and distance given the latitudes and longitudes of an initial and terminus point. Input coordinates can be given as python arrays, lists/tuples, scalars or numpy/Numeric/numarray arrays. Optimized for objects that support the Python buffer protocol (regular python and numpy array objects). Download: http://code.google.com/p/pyproj/downloads/list Requirements: python 2.4 or higher. Example scripts are in 'test' subdirectory of source distribution. The 'test()' function will run the examples in the docstrings. Contact: Jeffrey Whitaker >> from pyproj import Proj >>> p = Proj(proj='utm',zone=10,ellps='WGS84') # 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') # 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") >>> 'x=%12.3f y=%12.3f (meters)' % p(-114.057222, 51.045) 'x=-1783486.760 y= 6193833.196 (meters)' >>> p = Proj("+init=epsg:32667",preserve_units=True) >>> 'x=%12.3f y=%12.3f (feet)' % p(-114.057222, 51.045) 'x=-5851322.810 y=20320934.409 (feet)' """ # if projparams is None, use kwargs. if projparams is None: if len(kwargs) == 0: raise RuntimeError('no projection control parameters specified') else: projstring = _dict2string(kwargs) elif type(projparams) == str: # if projparams is a string, interpret as a proj4 init string. projstring = projparams else: # projparams a dict projstring = _dict2string(projparams) # make sure units are meters if preserve_units is False. if not projstring.count('+units=') and not preserve_units: projstring = '+units=m '+projstring else: kvpairs = [] for kvpair in projstring.split(): if kvpair.startswith('+units') and not preserve_units: k,v = kvpair.split('=') kvpairs.append(k+'=m ') else: kvpairs.append(kvpair+' ') projstring = ''.join(kvpairs) # look for EPSG, replace with epsg (EPSG only works # on case-insensitive filesystems). projstring = projstring.replace('EPSG','epsg') return _Proj.__new__(self, projstring) def __call__(self, *args, **kw): #,lon,lat,inverse=False,radians=False,errcheck=False): """ 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 'radians' is True (default is False) the units of lon/lat are radians instead of degrees. 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. Instead of calling with lon, lat, a single ndarray of shape n,2 may be used, and one of the same shape will be returned; this is more efficient. 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. """ inverse = kw.get('inverse', False) radians = kw.get('radians', False) errcheck = kw.get('errcheck', False) #if len(args) == 1: # latlon = np.array(args[0], copy=True, # order='C', dtype=float, ndmin=2) # if inverse: # _Proj._invn(self, latlon, radians=radians, errcheck=errcheck) # else: # _Proj._fwdn(self, latlon, radians=radians, errcheck=errcheck) # return latlon lon, lat = args # process inputs, making copies that support buffer API. inx, xisfloat, xislist, xistuple = _copytobuffer(lon) iny, yisfloat, yislist, yistuple = _copytobuffer(lat) # call proj4 functions. inx and iny modified in place. if inverse: _Proj._inv(self, inx, iny, radians=radians, errcheck=errcheck) else: _Proj._fwd(self, inx, iny, radians=radians, errcheck=errcheck) # if inputs were lists, tuples or floats, convert back. outx = _convertback(xisfloat,xislist,xistuple,inx) outy = _convertback(yisfloat,yislist,xistuple,iny) return outx, outy def is_latlong(self): """returns True if projection in geographic (lon/lat) coordinates""" return _Proj.is_latlong(self) def is_geocent(self): """returns True if projection in geocentric (x/y) coordinates""" return _Proj.is_geocent(self) def transform(p1, p2, x, y, z=None, radians=False): """ 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) >>> "%12.3f %12.3f" % (x2,y2) ' 1402285.991 5076292.423' """ # process inputs, making copies that support buffer API. inx, xisfloat, xislist, xistuple = _copytobuffer(x) iny, yisfloat, yislist, yistuple = _copytobuffer(y) if z is not None: inz, zisfloat, zislist, zistuple = _copytobuffer(z) else: inz = None # call pj_transform. inx,iny,inz buffers modified in place. _transform(p1,p2,inx,iny,inz,radians) # if inputs were lists, tuples or floats, convert back. outx = _convertback(xisfloat,xislist,xistuple,inx) outy = _convertback(yisfloat,yislist,xistuple,iny) if inz is not None: outz = _convertback(zisfloat,zislist,zistuple,inz) return outx, outy, outz else: return outx, outy def _copytobuffer(x): """ return a copy of x as an object that supports the python Buffer API (python array if input is float, list or tuple, numpy array if input is a numpy array). returns copyofx, isfloat, islist, istuple (islist is True if input is a list, istuple is true if input is a tuple, isfloat is true if input is a float). """ # make sure x supports Buffer API and contains doubles. isfloat = False; islist = False; istuple = False # first, if it's a numpy array scalar convert to float # (array scalars don't support buffer API) if hasattr(x,'shape') and x.shape == (): x = float(x) try: # typecast numpy arrays to double. # (this makes a copy - which is crucial # since buffer is modified in place) x.dtype.char inx = x.astype('d') except: try: # perhaps they are Numeric/numarrays? x.typecode() inx = x.astype('d') except: # perhaps they are regular python arrays? try: x.typecode inx = array('d',x) except: # try to convert to python array # a list. if type(x) == list: inx = array('d',x) islist = True # a tuple. elif type(x) == tuple: inx = array('d',x) istuple = True # a scalar? else: try: x = float(x) inx = array('d',(x,)) isfloat = True except: raise TypeError('input must be an array, list, tuple or scalar') return inx,isfloat,islist,istuple def _convertback(isfloat,islist,istuple,inx): # if inputs were lists, tuples or floats, convert back to original type. if isfloat: return inx[0] elif islist: return inx.tolist() elif istuple: return tuple(inx) else: return inx def _dict2string(projparams): # convert a dict to a proj4 string. pjargs = [] for key,value in projparams.items(): pjargs.append('+'+key+"="+str(value)+' ') return ''.join(pjargs) class Geod(_Geod): """ performs forward and inverse geodetic, or Great Circle, computations. The forward computation (using the 'fwd' method) involves determining latitude, longitude and back azimuth of a terminus point given the latitude and longitude of an initial point, plus azimuth and distance. The inverse computation (using the 'inv' method) involves determining the forward and back azimuths and distance given the latitudes and longitudes of an initial and terminus point. """ def __new__(self, initparams=None, **kwargs): """ initialize a Geod class instance. Geodetic parameters for specifying the ellipsoid can be given in a dictionary 'initparams', as keyword arguments, or as as proj4 geod initialization string. Following is a list of the ellipsoids that may be defined using the 'ellps' keyword: MERIT a=6378137.0 rf=298.257 MERIT 1983 SGS85 a=6378136.0 rf=298.257 Soviet Geodetic System 85 GRS80 a=6378137.0 rf=298.257222101 GRS 1980(IUGG, 1980) IAU76 a=6378140.0 rf=298.257 IAU 1976 airy a=6377563.396 b=6356256.910 Airy 1830 APL4.9 a=6378137.0. rf=298.25 Appl. Physics. 1965 NWL9D a=6378145.0. rf=298.25 Naval Weapons Lab., 1965 mod_airy a=6377340.189 b=6356034.446 Modified Airy andrae a=6377104.43 rf=300.0 Andrae 1876 (Den., Iclnd.) aust_SA a=6378160.0 rf=298.25 Australian Natl & S. Amer. 1969 GRS67 a=6378160.0 rf=298.2471674270 GRS 67(IUGG 1967) bessel a=6377397.155 rf=299.1528128 Bessel 1841 bess_nam a=6377483.865 rf=299.1528128 Bessel 1841 (Namibia) clrk66 a=6378206.4 b=6356583.8 Clarke 1866 clrk80 a=6378249.145 rf=293.4663 Clarke 1880 mod. CPM a=6375738.7 rf=334.29 Comm. des Poids et Mesures 1799 delmbr a=6376428. rf=311.5 Delambre 1810 (Belgium) engelis a=6378136.05 rf=298.2566 Engelis 1985 evrst30 a=6377276.345 rf=300.8017 Everest 1830 evrst48 a=6377304.063 rf=300.8017 Everest 1948 evrst56 a=6377301.243 rf=300.8017 Everest 1956 evrst69 a=6377295.664 rf=300.8017 Everest 1969 evrstSS a=6377298.556 rf=300.8017 Everest (Sabah & Sarawak) fschr60 a=6378166. rf=298.3 Fischer (Mercury Datum) 1960 fschr60m a=6378155. rf=298.3 Modified Fischer 1960 fschr68 a=6378150. rf=298.3 Fischer 1968 helmert a=6378200. rf=298.3 Helmert 1906 hough a=6378270.0 rf=297. Hough intl a=6378388.0 rf=297. International 1909 (Hayford) krass a=6378245.0 rf=298.3 Krassovsky, 1942 kaula a=6378163. rf=298.24 Kaula 1961 lerch a=6378139. rf=298.257 Lerch 1979 mprts a=6397300. rf=191. Maupertius 1738 new_intl a=6378157.5 b=6356772.2 New International 1967 plessis a=6376523. b=6355863. Plessis 1817 (France) SEasia a=6378155.0 b=6356773.3205 Southeast Asia walbeck a=6376896.0 b=6355834.8467 Walbeck WGS60 a=6378165.0 rf=298.3 WGS 60 WGS66 a=6378145.0 rf=298.25 WGS 66 WGS72 a=6378135.0 rf=298.26 WGS 72 WGS84 a=6378137.0 rf=298.257223563 WGS 84 sphere a=6370997.0 b=6370997.0 Normal Sphere (r=6370997) The parameters of the ellipsoid may also be set directly using the 'a' (semi-major or equatorial axis radius) keyword, and any one of the following keywords: 'b' (semi-minor, or polar axis radius), 'e' (eccentricity), 'es' (eccentricity squared), 'f' (flattening), or 'rf' (reciprocal flattening). See the proj documentation (http://proj.maptools.org) for more information about specifying ellipsoid parameters (specifically, the chapter 'Specifying the Earth's figure' in the main Proj users manual). Example usage: >>> from pyproj import Geod >>> g = Geod(ellps='clrk66') # Use Clarke 1966 ellipsoid. >>> # specify the lat/lons of some cities. >>> boston_lat = 42.+(15./60.); boston_lon = -71.-(7./60.) >>> portland_lat = 45.+(31./60.); portland_lon = -123.-(41./60.) >>> newyork_lat = 40.+(47./60.); newyork_lon = -73.-(58./60.) >>> london_lat = 51.+(32./60.); london_lon = -(5./60.) >>> # compute forward and back azimuths, plus distance >>> # between Boston and Portland. >>> az12,az21,dist = g.inv(boston_lon,boston_lat,portland_lon,portland_lat) >>> "%7.3f %6.3f %12.3f" % (az12,az21,dist) '-66.531 75.654 4164192.708' >>> # compute latitude, longitude and back azimuth of Portland, >>> # given Boston lat/lon, forward azimuth and distance to Portland. >>> endlon, endlat, backaz = g.fwd(boston_lon, boston_lat, az12, dist) >>> "%6.3f %6.3f %13.3f" % (endlat,endlon,backaz) '45.517 -123.683 75.654' >>> # compute the azimuths, distances from New York to several >>> # cities (pass a list) >>> lons1 = 3*[newyork_lon]; lats1 = 3*[newyork_lat] >>> lons2 = [boston_lon, portland_lon, london_lon] >>> lats2 = [boston_lat, portland_lat, london_lat] >>> az12,az21,dist = g.inv(lons1,lats1,lons2,lats2) >>> for faz,baz,d in list(zip(az12,az21,dist)): "%7.3f %7.3f %9.3f" % (faz,baz,d) ' 54.663 -123.448 288303.720' '-65.463 79.342 4013037.318' ' 51.254 -71.576 5579916.649' >>> g2 = Geod('+ellps=clrk66') # use proj4 style initialization string >>> az12,az21,dist = g2.inv(boston_lon,boston_lat,portland_lon,portland_lat) >>> "%7.3f %6.3f %12.3f" % (az12,az21,dist) '-66.531 75.654 4164192.708' """ # if initparams is None, use kwargs. if initparams is None: if len(kwargs) == 0: raise RuntimeError('no ellipsoid control parameters specified') else: initstring = _dict2string(kwargs) elif type(initparams) == str: # if projparams is a string, interpret as a proj4 init string. initstring = initparams else: # projparams a dict initstring = _dict2string(initparams) # make sure units are meters. if not initstring.count('+units='): initstring = '+units=m '+initstring else: kvpairs = [] for kvpair in initstring.split(): if kvpair.startswith('+units'): k,v = kvpair.split('=') kvpairs.append(k+'=m ') else: kvpairs.append(kvpair+' ') initstring = ''.join(kvpairs) # first try a Proj class (catches errors properly) projstring = initstring + ' +proj=latlon' p = Proj(projstring) # this is never used return _Geod.__new__(self, initstring) def fwd(self, lons, lats, az, dist, radians=False): """ forward transformation - Returns longitudes, latitudes and back azimuths of terminus points given longitudes (lons) and latitudes (lats) of initial points, plus forward azimuths (az) and distances (dist). Works with numpy and regular python array objects, python sequences and scalars. if radians=True, lons/lats and azimuths are radians instead of degrees. Distances are in meters. """ # process inputs, making copies that support buffer API. inx, xisfloat, xislist, xistuple = _copytobuffer(lons) iny, yisfloat, yislist, yistuple = _copytobuffer(lats) inz, zisfloat, zislist, zistuple = _copytobuffer(az) ind, disfloat, dislist, distuple = _copytobuffer(dist) # call geod_for function. inputs modified in place. _Geod._fwd(self, inx, iny, inz, ind, radians=radians) # if inputs were lists, tuples or floats, convert back. outx = _convertback(xisfloat,xislist,xistuple,inx) outy = _convertback(yisfloat,yislist,xistuple,iny) outz = _convertback(zisfloat,zislist,zistuple,inz) return outx, outy, outz def inv(self, lons1, lats1, lons2, lats2, radians=False): """ inverse transformation - Returns forward and back azimuths, plus distances between initial points (specified by lons1, lats1) and terminus points (specified by lons2, lats2). Works with numpy and regular python array objects, python sequences and scalars. if radians=True, lons/lats and azimuths are radians instead of degrees. Distances are in meters. """ # process inputs, making copies that support buffer API. inx, xisfloat, xislist, xistuple = _copytobuffer(lons1) iny, yisfloat, yislist, yistuple = _copytobuffer(lats1) inz, zisfloat, zislist, zistuple = _copytobuffer(lons2) ind, disfloat, dislist, distuple = _copytobuffer(lats2) # call geod_inv function. inputs modified in place. _Geod._inv(self, inx, iny, inz, ind, radians=radians) # if inputs were lists, tuples or floats, convert back. outx = _convertback(xisfloat,xislist,xistuple,inx) outy = _convertback(yisfloat,yislist,xistuple,iny) outz = _convertback(zisfloat,zislist,zistuple,inz) return outx, outy, outz def npts(self, lon1, lat1, lon2, lat2, npts, radians=False): """ Given a single initial point and terminus point (specified by python floats lon1,lat1 and lon2,lat2), returns a list of longitude/latitude pairs describing npts equally spaced intermediate points along the geodesic between the initial and terminus points. if radians=True, lons/lats are radians instead of degrees. Example usage: >>> from pyproj import Geod >>> g = Geod(ellps='clrk66') # Use Clarke 1966 ellipsoid. >>> # specify the lat/lons of Boston and Portland. >>> boston_lat = 42.+(15./60.); boston_lon = -71.-(7./60.) >>> portland_lat = 45.+(31./60.); portland_lon = -123.-(41./60.) >>> # find ten equally spaced points between Boston and Portland. >>> lonlats = g.npts(boston_lon,boston_lat,portland_lon,portland_lat,10) >>> for lon,lat in lonlats: '%6.3f %7.3f' % (lat, lon) '43.528 -75.414' '44.637 -79.883' '45.565 -84.512' '46.299 -89.279' '46.830 -94.156' '47.149 -99.112' '47.251 -104.106' '47.136 -109.100' '46.805 -114.051' '46.262 -118.924' """ lons, lats = _Geod._npts(self,lon1,lat1,lon2,lat2,npts,radians=radians) return list(zip(lons, lats)) def test(): """run the examples in the docstrings using the doctest module""" import doctest, pyproj doctest.testmod(pyproj,verbose=True) if __name__ == "__main__": test()