def rotate_from_ecef_to_enu(lat, lon):
"""rotate_from_ecef_to_enu(lat, lon)
Parameters
-----------
lat : array_like latitude (degrees)
lon : array_like longitude (degrees)
Returns
-------
versor : array_like euclid.Versor representing the transformation from ECEF
to ENU
"""
## Note the negative sign on the latitude
return ned2enu.compose(charts.Pitch(lon)).compose(charts.Roll(-lat))
from isceobj.Util.geo import charts
## Function that converts a coordinate instance to ECEF
to_ecef = methodcaller('ecef')
## Function that converts a coordinate instance to LLH
to_llh = methodcaller('llh')
## Function that converts a coordinate instance to LTP
to_ltp = lambda inst, peg_point=None: inst.ltp(peg_point=peg_point)
## Function that converts a coordinate instance to SCH
to_sch = lambda inst, peg_point=None: inst.sch(peg_point=peg_point)
## <a href="http://mathworld.wolfram.com/AliasTransformation.html">Alias
## transformation</a> from
## <a href="http://en.wikipedia.org/wiki/North_east_down">North East Down</a>
## to <a href="http://en.wikipedia.org/wiki/Geodetic_system#Local_east.2C_north.2C_up_.28ENU.29_coordinates">East North Up</a>
ned2enu = charts.Roll(90).compose(charts.Pitch(90))
## <a href="http://mathworld.wolfram.com/AliasTransformation.html">Alias
## transformation</a> to <a href="http://en.wikipedia.org/wiki/North_east_down">
## NED</a> from <a href="http://en.wikipedia.org/wiki/Geodetic_system#Local_east.2C_north.2C_up_.28ENU.29_coordinates">ENU</a>
enu2ned = ~ned2enu
## A peg point is simple enough to be a more than a
##<a href="http://docs.python.org/library/collections.html#collections.namedtuple">
## namedtuple</a>.
PegPoint = namedtuple("PegPoint", "lat lon hdg")
## Latitude and Longitude pairs are common enough to get a namedtuple.
LatLon = namedtuple("LatLon", "lat lon")