polygon.ipynb

gistfile1.txt

# Functions converting coastline/country polygons to lon/lat traces
def polygons_to_traces(poly_paths, N_poly):
    ''' 
    pos arg 1. (poly_paths): paths to polygons
    pos arg 2. (N_poly): number of polygon to convert
    '''
    # init. plotting list
    data = dict(
        x=[],
        y=[],
        mode='lines',
        line=Line(color="black"),
        name=' '
    )

    for i_poly in range(N_poly):
        poly_path = poly_paths[i_poly]
        
        # get the Basemap coordinates of each segment
        coords_cc = np.array(
            [(vertex[0],vertex[1]) 
             for (vertex,code) in poly_path.iter_segments(simplify=False)]
        )
        
        # convert coordinates to lon/lat by 'inverting' the Basemap projection
        lon_cc, lat_cc = m(coords_cc[:,0],coords_cc[:,1], inverse=True)
        
        
        # add plot.ly plotting options
        data['x'] = data['x'] + lon_cc.to_list() + [np.nan]
        data['y'] = data['y'] + lat_cc.to_list() + [np.nan]
        
        # traces.append(make_scatter(lon_cc,lat_cc))
     
    return [data]