boundary crossing footprint computation fails

[jlaura]

Tested with a CT image that crosses the 180 boundary.

~/autocnet/autocnet/graph/node.py in footprint(self)
    641         if res is None:
    642             boundary = generate_boundary(self.geodata.raster_size[::-1])  # yx to xy
--> 643             footprint_latlon = generate_latlon_footprint(self.camera, boundary)
    644             footprint_latlon.FlattenTo2D()
    645             footprint_latlon = footprint_latlon.ExportToWkt()

~/anaconda3/envs/autocnet/lib/python3.6/site-packages/knoten/csm.py in generate_latlon_footprint(camera, boundary, semi_major, semi_minor)
    219             slope, b = regression.slope, regression.intercept
    220             current_ring.AddPoint(0 - 180, (slope*0 + b))
--> 221             current_ring.AddPoint(*switch_point)
    222             current_ring = ring
    223             current_ring.AddPoint(360 - 180, (slope*360 + b))

~/anaconda3/envs/autocnet/lib/python3.6/site-packages/osgeo/ogr.py in AddPoint(self, *args, **kwargs)
   6218     def AddPoint(self, *args, **kwargs):
   6219         """AddPoint(Geometry self, double x, double y, double z=0)"""
-> 6220         return _ogr.Geometry_AddPoint(self, *args, **kwargs)
   6221 
   6222 

TypeError: in method 'Geometry_AddPoint', argument 2 of type 'double'