Add functionality to plot a solution

[fillipe-gsm]

Description

According to this issue, it would be interesting to have a function to plot also the solution of a VPR solver. This PR creates a module for that.

There are two functions for plotting solutions. The first shows the routes with street outlines, and thus it requires an OSRM server available.

The second is simpler and plots only the edges between each delivery:

Of course, in large problems the plotting may become too messy. A suggestion to overcome this is to plot less routes. Thus, instead of attempting to select which routes would be the most appropriate, we leave the decision to the user. For that, there is an auxiliary variable route_indices_to_plot to help with that task.

[gabisurita]

I suggest plotting the routes over streets instead. OSRM can help you with that.

There's is code I wrote in the past that might help you.

import polyline
import folium

def route_wiring(points):
    coords_uri = ";".join(
        ["{},{}".format(point.lng, point.lat) for point in points]
    )

    response = requests.get(
        f"{OSRM_HOST}/route/v1/driving/{coords_uri}?overview=simplified" , 
        timeout=600,
    )

    data = response.json()
    line = data["routes"][0]["geometry"]

    return [Point(lng, lat) for lat, lng in polyline.decode(line)]

def plot_route(points):

    wiring = route_wiring(points)

    m = folium.Map(
        location=np.mean([[p.lat, p.lng] for p in wiring], axis=0),
        zoom_start=13,
        tiles='cartodbpositron',
    )

    folium.PolyLine([[p.lat, p.lng] for p in wiring]).add_to(m)

    folium.CircleMarker([points[0].lat, points[0].lng], color="#ff0000", fill=True, radius=2).add_to(m)

    for point in points[1:]:
        folium.CircleMarker([point.lat, point.lng], color="#000000", fill=True, radius=1).add_to(m)

    return m

[fillipe-gsm]

I suggest plotting the routes over streets instead. OSRM can help you with that.

There's is code I wrote in the past that might help you.

import polyline
import folium

def route_wiring(points):
    coords_uri = ";".join(
        ["{},{}".format(point.lng, point.lat) for point in points]
    )

    response = requests.get(
        f"{OSRM_HOST}/route/v1/driving/{coords_uri}?overview=simplified" , 
        timeout=600,
    )

    data = response.json()
    line = data["routes"][0]["geometry"]

    return [Point(lng, lat) for lat, lng in polyline.decode(line)]

def plot_route(points):

    wiring = route_wiring(points)

    m = folium.Map(
        location=np.mean([[p.lat, p.lng] for p in wiring], axis=0),
        zoom_start=13,
        tiles='cartodbpositron',
    )

    folium.PolyLine([[p.lat, p.lng] for p in wiring]).add_to(m)

    folium.CircleMarker([points[0].lat, points[0].lng], color="#ff0000", fill=True, radius=2).add_to(m)

    for point in points[1:]:
        folium.CircleMarker([point.lat, point.lng], color="#000000", fill=True, radius=1).add_to(m)

    return m

Thanks for the suggestion! I adapted your code to plot all routes in a solution. Also, I decided to keep the previous function as fallback for a simpler visualization without the OSRM request (and mostly because it was already done :slightly_smiling_face: ), but if you wish we can remove and keep only the main one.