how to create moving turtles out of a shapefile in Netlogo - gis

Question

I'm just starting with using Netlogo to create an Agent Based Model. I have two shapefiles I want to use: a network map of a city (line-shapefile) and a point-shapefile of scooters in the city. The idea is to have them drive through the city on the lines of the network shapefile. Since I am new to Netlogo, I only managed to load these shapefiles in my model. Could someone give me a headstart by helping me to create turtles from the scooter registrations (points) and let them move over the network lines. I have found little help so far on the internet and it won't work with trial and error. So far, my code is just this:
extensions [ gis ]
to load
ca
let network gis:load-dataset "Roads_Asmterdam.shp"
foreach gis:feature-list-of network
[ gis:set-drawing-color white
gis:draw ? 0.3
]
let people gis:load-dataset "scooters_Amsterdam.shp"
foreach gis:feature-list-of people
[ gis:set-drawing-color blue
gis:draw people 3
]
end
So, as far as I know, I need a to go function where I want to move the turtles. And I need a function to create possible moving turtles out of the point-shapefile, but also I need to let them know to only use the lines instead of the whole area.
Many thanks in advance!

Answer 1

After loading the lines shape file you need to convert these into a network of agents/turtles and link them. NetLogo doesn't do that for you, you need to iterate over all the features, line segments and coordinates yourself. Then you need to place the scooters onto the coordinates from the line network, and then you can "ask" them to move around.
Here's what I came up with:
extensions [ gis ]
globals [ roads-dataset scooter-dataset ]
breed [ nodes node ]
breed [ scooters scooter ]
breed [ walkers walker ]
walkers-own [ wlocation ]
scooters-own [slocation]
to setup
; reset
clear-all
reset-ticks
; load data set
gis:load-coordinate-system (word "C:/Program Files/NetLogo 5.3.1/app/models/Code Examples/GIS/data/WGS_84_Geographic.prj")
set roads-dataset gis:load-dataset "C:/shape/roads.shp"
set scooter-dataset gis:load-dataset "C:/shape/scooter.shp"
gis:set-world-envelope (gis:envelope-of roads-dataset)
; draw data set
gis:set-drawing-color blue
gis:draw roads-dataset 1
make-road-network
end
to make-road-network
clear-links
let first-node nobody
let previous-node nobody
foreach gis:feature-list-of roads-dataset [ ; each polyline
foreach gis:vertex-lists-of ? [ ; each polyline segment / coordinate pair
foreach ? [ ; each coordinate
let location gis:location-of ?
if not empty? location [ ; some coordinates are empty []
create-nodes 1 [
set color green
set size 1
set xcor item 0 location
set ycor item 1 location
set hidden? true
if first-node = nobody [
set first-node self
]
if previous-node != nobody [
create-link-with previous-node
]
set previous-node self
]
]
]
set previous-node nobody
]
]
; connect adjacent polylines/roads
ask nodes [ create-links-with other nodes in-radius 0.001 ]
end
to add-agents
create-walkers 5 [
set color red
set wlocation one-of nodes
move-to wlocation
]
end
to add-scooters
foreach gis:feature-list-of scooter-dataset [
foreach gis:vertex-lists-of ? [
let location gis:location-of (first ?)
create-scooters 1 [
set color yellow
set size 1
set xcor item 0 location
set ycor item 1 location
let nearest-node min-one-of (nodes in-radius 10)[distance myself]
set slocation nearest-node
move-to slocation
]
]
]
end
to go
ask walkers [
let new-location one-of [link-neighbors] of wlocation
move-to new-location
set wlocation new-location
]
ask scooters [
let new-location one-of [link-neighbors] of slocation
move-to new-location
set slocation new-location
]
end
Some resources and example code I found particularly helpful:
NetLogo Programming Guide & example models about "walking" and "networks" that come with NetLogo
NetLogo Bag of Tricks - Venice Example Code
Duncan Golicher: Importing points into Netlogo and forming a network