Orthographic projection gives wrong results when considering lines crossing international date line

[Damiano Monelli]

The method ``openquake.hazardlib.geo.utils.get_orthographic_projection`` provides inconsistent results when applying the projection function to a line that crosses the international date line.

In particular given a line that crosses the IDL, converting the coordinates to the cartesian space and then back to spherical coordinates does not give the original values, below an example:

>>> from openquake.hazardlib.geo import utils
>>>
>>>
>>> west = 179.0
>>> east = -179.0
>>> south = -1.
>>> north = 1.
>>> proj = utils.get_orthographic_projection(west, east, south, north)
>>>
>>> lons = [179.0, -179.0]
>>> lats = [-1, 1]
>>>
>>> xx, yy = proj(lons, lats)
>>>
>>> new_lons, new_lats = proj(xx, yy, reverse=True)
>>> new_lons
array([-181., -179.])

The original longitudes ([179.0, -179.0]) are not reproduced, what I get is ([-181., -179.0])

This error has been found when running a hazard calculation with OpenQuake with a source model considering a fault crossing the IDL, in this case OQ gives an error because longitude values are not in the expected range [-180., 180]

[Lars Butler (lars-butler)]

Resolved by https://github.com/gem/oq-hazardlib/pull/116.

[Lars Butler (lars-butler)]

Another patch to cover more cases: https://github.com/gem/oq-hazardlib/pull/117