def __init__(self,
projparams,
llcrnrlon,
llcrnrlat,
urcrnrlon,
urcrnrlat,
urcrnrislatlon=True):
"""
initialize a Proj class instance.
Input 'projparams' is a dictionary containing proj map
projection control parameter key/value pairs.
See the proj documentation (http://www.remotesensing.org/proj/)
for details.
llcrnrlon,llcrnrlat are lon and lat (in degrees) of lower left hand corner
of projection region.
urcrnrlon,urcrnrlat are lon and lat (in degrees) of upper right hand corner
of projection region if urcrnrislatlon=True (default). Otherwise,
urcrnrlon,urcrnrlat are x,y in projection coordinates (units meters),
assuming the lower left corner is x=0,y=0.
"""
# set units to meters.
if not projparams.has_key('units'):
projparams['units'] = 'm'
elif projparams['units'] != 'm':
print 'resetting units to meters ...'
projparams['units'] = 'm'
self.projparams = projparams
# make sure proj parameter specified.
# (no other checking done in proj parameters)
if 'proj' not in projparams.keys():
raise KeyError, "need to specify proj parameter"
if 'R' not in projparams.keys() and 'a' and 'b' not in projparams.keys(
):
raise KeyError, "need to specify R (perfect sphere radius), or a and b (major and minor sphere radii)"
# build proj string.
self.proj4cmd = []
for key, value in map(None, projparams.keys(), projparams.values()):
if key == 'x_0' or key == 'y_0':
# x_0 and y_0 are set based on llcrnrlon,llcrnrlat.
pass
else:
self.proj4cmd.append('+' + key + "=" + str(value) + ' ')
self.projection = projparams['proj']
# rmajor is the semi-major axis.
# rminor is the semi-minor axis.
# esq is eccentricity squared.
try:
self.rmajor = projparams['a']
self.rminor = projparams['b']
except:
self.rmajor = projparams['R']
self.rminor = self.rmajor
if self.rmajor == self.rminor:
self.ellipsoid = False
else:
self.ellipsoid = True
self.flattening = (self.rmajor - self.rminor) / self.rmajor
self.esq = (self.rmajor**2 - self.rminor**2) / self.rmajor**2
self.llcrnrlon = llcrnrlon
self.llcrnrlat = llcrnrlat
if self.projection not in ['cyl', 'ortho', 'moll', 'robin']:
self._proj4 = proj4.Proj(''.join(self.proj4cmd))
llcrnrx, llcrnry = self._fwd(llcrnrlon, llcrnrlat)
elif self.projection == 'cyl':
llcrnrx = llcrnrlon
llcrnry = llcrnrlat
elif self.projection == 'ortho':
self._proj4 = proj4.Proj(''.join(self.proj4cmd))
llcrnrx = -self.rmajor
llcrnry = -self.rmajor
urcrnrx = -llcrnrx
urcrnry = -llcrnry
elif self.projection == 'moll' or self.projection == 'robin':
self._proj4 = proj4.Proj(''.join(self.proj4cmd))
xtmp, urcrnry = self._fwd(projparams['lon_0'], 90.)
urcrnrx, xtmp = self._fwd(projparams['lon_0'] + 180., 0)
llcrnrx = -urcrnrx
llcrnry = -urcrnry
# compute x_0, y_0 so ll corner of domain is x=0,y=0.
# note that for 'cyl' x,y == lon,lat
self.proj4cmd.append("+x_0=" + str(-llcrnrx) + ' ')
self.projparams['x_0'] = -llcrnrx
self.proj4cmd.append("+y_0=" + str(-llcrnry) + ' ')
self.projparams['y_0'] = -llcrnry
# reset with x_0, y_0.
if self.projection != 'cyl':
self._proj4 = proj4.Proj(''.join(self.proj4cmd))
llcrnry = 0.
llcrnrx = 0.
else:
llcrnrx = llcrnrlon
llcrnry = llcrnrlat
if urcrnrislatlon:
self.urcrnrlon = urcrnrlon
self.urcrnrlat = urcrnrlat
if self.projection not in ['ortho', 'moll', 'robin']:
urcrnrx, urcrnry = self._fwd(urcrnrlon, urcrnrlat)
elif self.projection == 'ortho':
urcrnrx = 2. * self.rmajor
urcrnry = 2. * self.rmajor
elif self.projection == 'moll' or self.projection == 'robin':
xtmp, urcrnry = self._fwd(projparams['lon_0'], 90.)
urcrnrx, xtmp = self._fwd(projparams['lon_0'] + 180., 0)
else:
urcrnrx = urcrnrlon
urcrnry = urcrnrlat
urcrnrlon, urcrnrlat = self._inv(urcrnrx, urcrnry)
self.urcrnrlon = urcrnrlon
self.urcrnrlat = urcrnrlat
# corners of domain.
self.llcrnrx = llcrnrx
self.llcrnry = llcrnry
self.urcrnrx = urcrnrx
self.urcrnry = urcrnry
if urcrnrx > llcrnrx:
self.xmin = llcrnrx
self.xmax = urcrnrx
else:
self.xmax = llcrnrx
self.xmin = urcrnrx
if urcrnry > llcrnry:
self.ymin = llcrnry
self.ymax = urcrnry
else:
self.ymax = llcrnry
self.ymin = urcrnry
def __init__(self,
projparams,
llcrnrlon,
llcrnrlat,
urcrnrlon,
urcrnrlat,
urcrnrislatlon=True):
"""
initialize a Proj class instance.
Input 'projparams' is a dictionary containing proj map
projection control parameter key/value pairs.
See the proj documentation (http://www.remotesensing.org/proj/)
for details.
llcrnrlon,llcrnrlat are lon and lat (in degrees) of lower left hand corner
of projection region.
urcrnrlon,urcrnrlat are lon and lat (in degrees) of upper right hand corner
of projection region if urcrnrislatlon=True (default). Otherwise,
urcrnrlon,urcrnrlat are x,y in projection coordinates (units meters),
assuming the lower left corner is x=0,y=0.
"""
# set units to meters.
if not projparams.has_key('units'):
projparams['units'] = 'm'
elif projparams['units'] != 'm':
print 'resetting units to meters ...'
projparams['units'] = 'm'
self.projparams = projparams
# make sure proj parameter specified.
# (no other checking done in proj parameters)
if 'proj' not in projparams.keys():
raise KeyError, "need to specify proj parameter"
# build proj string.
self.proj4md = []
for key, value in map(None, projparams.keys(), projparams.values()):
if key == 'x_0' or key == 'y_0':
# x_0 and y_0 are set based on llcrnrlon,llcrnrlat.
pass
else:
self.proj4md.append('+' + key + "=" + str(value) + ' ')
self.projection = projparams['proj']
self.llcrnrlon = llcrnrlon
self.llcrnrlat = llcrnrlat
if self.projection != 'cyl':
self._proj4 = proj4.Proj(''.join(self.proj4md))
llcrnrx, llcrnry = self._fwd(llcrnrlon, llcrnrlat)
# compute x_0, y_0 so ll corner of domain is x=0,y=0.
# note that for 'cyl' x,y == lon,lat
# and for 'merc' x,y == lon,y
self.proj4md.append("+x_0=" + str(-llcrnrx) + ' ')
self.projparams['x_0'] = -llcrnrx
self.proj4md.append("+y_0=" + str(-llcrnry) + ' ')
self.projparams['y_0'] = -llcrnry
# reset with x_0, y_0.
if self.projection != 'cyl':
self._proj4 = proj4.Proj(''.join(self.proj4md))
llcrnry = 0.
if self.projection == 'merc':
llcrnrx = llcrnrlon
else:
llcrnrx = 0.
else:
llcrnrx = llcrnrlon
llcrnry = llcrnrlat
if urcrnrislatlon:
self.urcrnrlon = urcrnrlon
self.urcrnrlat = urcrnrlat
urcrnrx, urcrnry = self._fwd(urcrnrlon, urcrnrlat)
else:
urcrnrx = urcrnrlon
urcrnry = urcrnrlat
urcrnrlon, urcrnrlat = self._inv(urcrnrx, urcrnry)
self.urcrnrlon = urcrnrlon
self.urcrnrlat = urcrnrlat
# corners of domain.
self.llcrnrx = llcrnrx
self.llcrnry = llcrnry
self.urcrnrx = urcrnrx
self.urcrnry = urcrnry
if urcrnrx > llcrnrx:
self.xmin = llcrnrx
self.xmax = urcrnrx
else:
self.xmax = llcrnrx
self.xmin = urcrnrx
if urcrnry > llcrnry:
self.ymin = llcrnry
self.ymax = urcrnry
else:
self.ymax = llcrnry
self.ymin = urcrnry