__init__.py 文件源码

def drawgreatcircle(self,lon1,lat1,lon2,lat2,del_s=100.,**kwargs):
        """
        Draw a great circle on the map from the longitude-latitude
        pair ``lon1,lat1`` to ``lon2,lat2``

        .. tabularcolumns:: |l|L|

        ==============   =======================================================
        Keyword          Description
        ==============   =======================================================
        del_s            points on great circle computed every del_s kilometers
                         (default 100).
        \**kwargs        other keyword arguments are passed on to :meth:`plot`
                         method of Basemap instance.
        ==============   =======================================================

        .. note::
         Cannot handle situations in which the great circle intersects
         the edge of the map projection domain, and then re-enters the domain.

        Returns a matplotlib.lines.Line2D object.
        """
        # use great circle formula for a perfect sphere.
        gc = pyproj.Geod(a=self.rmajor,b=self.rminor)
        az12,az21,dist = gc.inv(lon1,lat1,lon2,lat2)
        npoints = int((dist+0.5*1000.*del_s)/(1000.*del_s))
        lonlats = gc.npts(lon1,lat1,lon2,lat2,npoints)
        lons = [lon1]; lats = [lat1]
        for lon, lat in lonlats:
            lons.append(lon)
            lats.append(lat)
        lons.append(lon2); lats.append(lat2)
        x, y = self(lons, lats)
        return self.plot(x,y,**kwargs)