Great circle

In [1]:
import pyproj
import numpy as np
import geoviews as gv
import geoviews.feature as gf
from bokeh.sampledata.airport_routes import airports, routes

%output fig='svg' size=250

Define data

In [2]:
def get_circle_path(start, end, samples=200):
    sx, sy = start
    ex, ey = end
    g = pyproj.Geod(ellps='WGS84')
    (az12, az21, dist) = g.inv(sx, sy, ex, ey)
    lonlats = g.npts(sx, sy, ex, ey, 200)
    return np.array([(sx, sy)]+lonlats+[(ex, ey)])

# Compute great-circle paths for all US flight routes from Honolulu
paths = []
honolulu = (-157.9219970703125, 21.318700790405273)
routes = routes[routes.SourceID==3728]
airports = airports[airports.AirportID.isin(list(routes.DestinationID)+[3728])]
for i, route in routes.iterrows():
    airport = airports[airports.AirportID==route.DestinationID].iloc[0]
    paths.append(get_circle_path(honolulu, (airport.Longitude, airport.Latitude)))

# Define Graph from Nodes and EdgePaths
path = gv.EdgePaths(paths)
points = gv.Nodes(airports, ['Longitude', 'Latitude', 'AirportID'], ['Name', 'City'])
graph = gv.Graph((routes, points, path), ['SourceID', 'DestinationID'])


In [3]:
%%opts Graph [width=600 height=400 tools=['hover']] (node_color='black' node_size=8)
(gf.ocean * * gf.lakes * graph * gf.coastline).redim.range(Longitude=(-170, -62), Latitude=(10, 75))

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