Open street map example

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Open street map example#

The zombie outbreak model showcases an ABM running on a map, using OpenStreetMapSpace.

using Agents
using Random
using CairoMakie
using OSMMakie
CairoMakie.activate!(px_per_unit = 1.0)

Update message: Agents v6

This is a new major version of Agents.jl with lots of cool stuff!
However, from this version onwards, we will stop posting update messages
to the REPL console!

If you want to be updated, follow this discourse post:

https://discourse.julialang.org/t/agents-jl-v6-releases-announcement-post/111678

(and see the CHANGELOG.md file online for a list of changes!)

The helper function is adapted from Agents.abmvideo and correctly displays animations in Jupyter notebooks

function abmvio(model;
    dt = 1, framerate = 30, frames = 300, title = "", showstep = true,
    figure = (size = (600, 600),), axis = NamedTuple(),
    recordkwargs = (compression = 23, format ="mp4"), kwargs...
)
    # title and steps
    abmtime_obs = Observable(abmtime(model))
    if title ≠ "" && showstep
        t = lift(x -> title*", time = "*string(x), abmtime_obs)
    elseif showstep
        t = lift(x -> "time = "*string(x), abmtime_obs)
    else
        t = title
    end

    axis = (title = t, titlealign = :left, axis...)
    # First frame
    fig, ax, abmobs = abmplot(model; add_controls = false, warn_deprecation = false, figure, axis, kwargs...)
    resize_to_layout!(fig)
    # Animation
    Makie.Record(fig; framerate, recordkwargs...) do io
        for j in 1:frames-1
            recordframe!(io)
            Agents.step!(abmobs, dt)
            abmtime_obs[] = abmtime(model)
        end
        recordframe!(io)
    end
end

abmvio (generic function with 1 method)

Agents for zombies and healthy humans

@agent struct Zombie(OSMAgent)
    infected::Bool
    speed::Float64
end

initialise model

function initialise_zombies(; seed = 1234)
    map_path = OSM.test_map()
    properties = Dict(:dt => 1 / 60)

    model = StandardABM(
        Zombie,
        OpenStreetMapSpace(map_path);
        agent_step! = zombie_step!,
        properties = properties,
        rng = Random.MersenneTwister(seed)
    )

    for id in 1:100
        start = random_position(model) ## At an intersection
        speed = rand(abmrng(model)) * 5.0 + 2.0 ## Random speed from 2-7kmph
        human = add_agent!(start, Zombie, model, false, speed)
        OSM.plan_random_route!(human, model; limit = 50) ## try 50 times to find a random route
    end

    # We'll add patient zero at a specific (longitude, latitude)
    start = OSM.nearest_road((9.9351811, 51.5328328), model)
    finish = OSM.nearest_node((9.945125635913511, 51.530876112711745), model)

    speed = rand(abmrng(model)) * 5.0 + 2.0 ## Random speed from 2-7kmph
    zombie = add_agent!(start, model, true, speed)
    plan_route!(zombie, finish, model)
    return model
end

initialise_zombies (generic function with 1 method)

Stepping function

function zombie_step!(agent, model)
    # Each agent will progress along their route
    # Keep track of distance left to move this step, in case the agent reaches its
    # destination early
    distance_left = move_along_route!(agent, model, agent.speed * model.dt)

    if is_stationary(agent, model) && rand(abmrng(model)) < 0.1
        # When stationary, give the agent a 10% chance of going somewhere else
        OSM.plan_random_route!(agent, model; limit = 50)
        # Start on new route, moving the remaining distance
        move_along_route!(agent, model, distance_left)
    end

    # Agents will be infected if they get too close (within 10m) to a zombie.
    if agent.infected
        map(i -> model[i].infected = true, nearby_ids(agent, model, 0.01))
    end
    return
end

zombie_step! (generic function with 1 method)

Animation#

zombie_color(agent) = agent.infected ? :green : :black
zombie_size(agent) = agent.infected ? 10 : 8
zombies = initialise_zombies()

vio = abmvio(zombies;
    title = "Zombie outbreak", framerate = 15, frames = 200,
    agent_color = zombie_color, agent_size = zombie_size
)

save("zombie.mp4", vio)
vio |> display

 Downloading artifact: osm_map_gottingen
[ Info: Created OSMGraph object with kwargs: `network_type=drive`, `weight_type=distance`, `graph_type=static`, `precompute_dijkstra_states=false`, `largest_connected_component=true`

This notebook was generated using Literate.jl.

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