def compute_node_positions(self):
        """
        Extracts the node positions based on the specified longitude and
        latitude keyword arguments.
        """
        xs = []
        ys = []
        self.locs = dict()

        for node in self.nodes:
            x = self.graph.node[node][self.node_lon]
            y = self.graph.node[node][self.node_lat]
            xs.append(x)
            ys.append(y)
            self.locs[node] = (x, y)

        self.node_coords = {"x": xs, "y": ys}
Extracts the node positions based on the specified longitude and
        latitude keyword arguments.